"How beautiful these are!" Ray exclaimed as he fondled Paula's bare tits. "So full and soft and white. I love to suck them, darling."
He bowed his head, and his lips settled warmly around an upthrust nipple. Paula drew in her breath as exquisite sensations radiated from the tip of the tit Ray was sucking.
"Ooh, darling… lover… ooh, that feels so good!" Paula exclaimed.
He switched to her other tit and licked it thoroughly before clamping his lips around the stiff nipple. He lashed the nipple with his tongue and bit it gently as he sucked.
Kathy stared at this, and her own nipples felt so hot and tight she could hardly keep from touching them through her nightie. But she managed to restrain herself-for the moment.
Ray rubbed his clean-shaven face back and forth across his wife's full tits, sucking and licking to his heart's content. Her nipples popped in and out of his mouth as they danced atop the soft, springy mounds. Kathy noticed how high her mother's nipples were standing and how Ray's saliva made them gleam in the glow from the bedside lamp.
The fact that her mother and Ray were making love with the light on surprised Kathy and shocked her a little. But how else would she have been able to watch what was going on?
Ray transferred his mouth to Paula's waiting lips. He kissed her long and deeply. Kathy's mouth grew dry and her throat tightened.
Ray backed up, causing the covers to drag lower on his body and Paula's. He began to kiss her around the waist. Kathy watched his hand stroke her mother's belly, then his mouth move next to her navel and his tongue snake out to enter her belly button, licking noisily.
Paula squirmed. "Ooh, darling, you're driving me wild!" she exclaimed in a voice which was low pitched and tense with passion.
Ray moved lower along Paula's side, and the covers fell away from his ass. Kathy stared as he stroked her mother's thighs, then wedged his hand between them and tried to pry them open. At first Paula resisted, but then with a sigh, she let her legs part. Kathy gazed across the foot of the bed at her mother's cunt, nearly hidden from view by the thick blanket of dark hair.
As Ray placed his hand on Paula's soft, furry cunt, Kathy's pussy throbbed responsively. For a moment, she wished she were in her mother's place, receiving Ray's intimate caress. But as soon as her conscious mind became aware of this desire, she repressed the thought. But she continued to watch and listen..
Paula writhed, rolling to and from on her cushiony ass, while Ray petted her pussy. Then suddenly he reared backward, thrusting his ass into the air as he aimed, his face toward Paula's cunt.
Kathy's eyes bugged. She didn't know which was more shocking-the direction in which Ray was now headed or the complete exposure of his cock and balls caused by the upward thrust of his hips. The teen girl stared in fascination at the brown, wrinkled sac, which contained her stepfather's balls, and at the big cock extending forward from above. His cock was huge! She'd had no idea a man's prick could become so long and brutally stiff! Earlier that day, she had glimpsed only the trunk of Ray's cock as he had stroked it in her mother's cunt, but now she saw the whole monstrous thing! She began to quiver wildly.
Her mother became very excited also when Ray started to press his face between her legs. She twisted away from him and damped her thighs tightly closed. "No, Ray," she panted. "Not that. Don't do that, darling."
He raised his head. "Why not, angel?"
"Because it isn't-decent."
Ray chuckled gently. "That's ridiculous. I enjoy doing it. And once you've found out what it's like, you'll enjoy it too.
"I won't!" she declared firmly. "So please don't."
"Baby… " he said, and chuckled again. His attitude was patient and tolerant. But he was determined.
He bent once more toward Paula's cunt and sought to pry her legs apart so he could gain access to it. She struggled. The idea of Ray kissing her pussy was very stimulating to Paula, but she had never engaged in oral sex, and she accepted the puritanical notion that it was wrong.
Spying from the balcony, Kathy became caught up in the drama, which was occurring on the bed as Ray gripped his wife's beautiful thighs and tried to wrench them open without hurting her. Kathy noted that her stepfather's cock remained very high and hard, its hard head gleaming dully as the lengthy organ swung back and forth.
Oh, Mama… Mama! Kathy cried inwardly, and rubbed her own warm thighs together beneath her flimsy nightgown.
She sympathized with her mother's attempts to resist the man's assault and yet, what a thrill it would be to watch him stick his face right down into her mother's cunt as he obviously wanted to do! Kathy had never even heard of this kind of sex, but it seemed as if it might be great fun!
As Ray gradually applied greater pressure, Paula's resolve weakened along with the muscles in her legs. She let out a distraught cry when she realized he was going to have his way with her. She convinced herself there was nothing she could do to stop it.
"No, Ray… ooh, noooh," Paula moaned. But she watched him hotly and expectantly as he lowered his head.
He began slowly, first merely brushing his lips up and down on the wet lips of her cunt while he held her thighs apart, his hands clamped around their soft undersides. Even this subtle caress sent a marvelous wave of pleasure coursing through her, and she breathed tensely. But she still murmured, "No…no… no… " Ray smiled to himself, knowing she would be saying yes in a little while. She was too much a female and altogether too horny not to appreciate this kind of treatment. He knew there was no better way to win and hold a woman in the bedroom than to eat her cunt well and often. And that was practically the only way to get a nice woman like Paula to suck cock, which was a pleasure that Ray, like most men, intensely enjoyed.
As he moved gently along her puffy slit, feeling her cunthairs tickling his lips and nose and chin, he breathed in her delightful fragrance. He extended his tongue a little and stroked it along her dewy crease, where the outer lips of her cunt were barely parted.
He let his tongue move upward across her hooded clit and a sharp tremor went through her. She gasped and stopped begging him to stop. She seemed to be holding her breath.
Bringing his thumbs into play, while continuing to keep his hands wrapped around her thighs, be gently drew the folded flesh away from her throbbing little clit and fluttered his tongue directly against the supersensitive little nubbin.
"Oooooh!" Paula cried. Her hands came down around the back of his head, grasping him to hold him in place.
She had been an easy conquest, Ray decided, and he wondered about the negligence of her former lovers for not putting forth the small effort which was required to break down her puritanical reserve.
Ray concentrated on Paula's palpitating clit licking it and sucking it deftly, while she moaned and gasped. Her massaging fingers actually hurt the back of his head as she gripped him fiercely, but this was a pain, which Ray appreciated.
Since it wasn't necessary for him to hold Paula's thighs apart any longer, he used his fingertips to tickle her cuntlips and to stretch her pussy open. This brought a stronger burst of fresh female fragrance to his nostrils and made it possible for him to stroke his tongue over every delicious inch of her smooth, slippery cunt. He culminated this phase of the act by sticking his wet tongue fully into the deep, clasping recess of her twat, so that the thickness of his tongue's base actually stretched the resilient little mouth as a cock would.
"Ooooh, God!" Paula shrieked, kicking her legs in the air. "Darling, I love it!"
Her teen daughter, standing outside the window, felt moisture burst from her cunt and dampen the crotchband of the thin panties she wore beneath her short nightgown.
Oh, he's really kissing her good down there! Kathy thought. I wonder how it feels? I wonder if I would like it?
She rubbed her cunt through the thin, clinging cloth, and she grew hotter. The feelings she was experiencing, and those she had experienced that afternoon, weren't new to her, because she had felt pleasurable sensations in her emit for as long as she could remember, but they certainly were new in intensity. She felt as if something was going to happen to her, but she didn't know what it was.
After pumping his tongue in and out of Paula's pussy several times, Ray lapped upward along her dripping folds, sucking up her thick, rich juice. Then he went to work on her clit once more, this time flogging the little bud with a rapid fluttering of his tongue.
Paula gasped, yelped, and let out a sustained, high-pitched "Eeeeeeee!"
Ray stopped just when she was about to come, and lifted his head.
"Ooooh… oooh… oooh…" Paula panted as she thrashed wildly, her thighs waving to and fro. "Get on me! Ooooh, get in me! Fuck me! Oh, God, Ray, do something!"
"Why don't you do something first?" he suggested, and flopped on onto his back. His immense cock swayed as it stuck rigidly upward from his hairy loins.
Kathy's eyes ached from the strain of staring at the fantastic happenings in her mother's bedroom. By now she had lifted her nightie and inserted her hand into her bikini briefs. She petted the damp, lightly furred lips of her cunt, while with the other hand, she plucked at her rigid nipples through the top of her nightie. Her young body throbbed with newly awakened desire.
Billy was as concerned as his sister about the change that had taken place in their lives. Deciding he would like to have a private talk with Kathy about it, he climbed out of bed, tiptoed across the hall to his sister's bedroom, and rapped softly on the door.
There was no answer. Perhaps she was already asleep, or perhaps she simply hadn't heard his knock, since it had been so light. But he didn't want to rap harder, for fear his mother and Ray would hear it and wonder what was going, on. If Kathy was asleep, he decided to wake her up. It wasn't very late, and what they had to discuss was important.
He quietly opened the door and peered into his sister's room. "Kathy?' Billy whispered. Still there was no answer.
He entered the room, closed the door behind him, and approached her bed. He could see, by the moonlight drifting in though the windows, that she wasn't there. But she had been there. The bed was slightly mussed and the covers were turned back.
Billy looked around, then noticed that one of her windows was open. He decided she must have stepped out on the balcony. Girls were funny. She probably was out there gazing at the moon and thinking about some guy at school.
Walking over to the window, Billy stuck his head out and was about to call Kathy's name when he saw her silhouetted against the light, which came from their mother's room. She was standing there looking in-spying on their mother and Ray. And she was playing with herself while she did it. Her nightie was up, and she had her hand in her flimsy, nearly transparent panties.
This sight gave Billy a sudden burst of excitement, causing his prick to fill with hot blood. His cock immediately lengthened out and became rigid, making a tent in the front of his pajamas.
He had been having horny thoughts about Kathy for several months-ever since he began to sprout hair around his cock and to get interested in girls. His own sister was cuter than most of the girls at school and, while he knew it was wrong to think of her in that way, he couldn't help wishing they could fool around together, just to find out what it was like.
Now his throat grew tight and his mouth grew dry. Acting on impulse, he stepped out onto the balcony. He moved quietly up behind his sister and touched her on the arm.
Kathy gasped and jumped. Turning, she looked into Billy's grinning face.
"So you've been spying, huh?" he whispered. He hadn't moved close enough to glance into his mother's room himself.
Kathy wanted to die. The fact that Billy had caught her peeping was bad enough, but he couldn't have failed to notice also that she had been stroking her cunt and tits. What he must think of her! She quickly jerked her hand out of her panties and let her nightgown fall to conceal her hips.
She tried to move past him and return to her roam, but Billy grasped her arm.
"Hey, wait a minute," he said. "What's going on in there?"
"Nothing!" Kathy whispered sharply, her voice hoarse. "Now let me go."
She tried to pull away from him, but he held her fast. As they struggled, she brushed against the front of his pajamas and was shocked to feel his hard cock nicking up. She jumped back as if a red-hot poker had touched her, and she gazed down at the lump in his pajamas.
Now it was Billy's turn to be embarrassed. But he covered it with bravado. He grasped Kathy by the arm and moved forward in front of their mother's window, pulling his sister along.
Together they looked into the room and listened to what was being said inside.
"No, Ray! Oooh, no, I can't do that!"
Ray had his thumb and index finger around the base of his erect cock and was swaying the shaft back and forth as he smiled up at Paula, who knelt beside him on the bed.
Billy stared at his mother's full, mature tits, and his cock throbbed harder than ever. He had the greatest boner of his life.
"But I did it for you," Ray said gently. "And I'm as clean as you are. We both bathed a little while ago."
"But I couldn't actually… put it in my mouth," Paula stammered as she stared at the huge rod with its swollen head.
"Good gosh!" Billy exclaimed under his breath.
Kathy just stared. Billy didn't, have to hold her any longer in order to make her stay.
"Then don't put it in your mouth," Ray said. "Just lick it a little."
"Noooh," Paula breathed. But Ray could tell she was thinking the suggestion over.
"Just put your tongue against it," he coaxed. "You'll find out it doesn't taste bad."
"Oh, Ray, it's so nasty," Paula said as she squirmed "No nastier than my licking your cunt. And that wasn't nasty at all."
Billy turned to his sister and asked in a hoarse whisper, "Did he really lick her down there?"
"Yessss," Kathy hissed softly, still staring into the lighted bedroom.
"Shit!" Billy exclaimed, and his hot young cock gave a jerk.
"Put your tongue on it, baby," Ray coaxed the twins mother, and he reached up to wrap his hand around the back of her head.
Billy felt a surge of hatred for Ray. What right did be have to ask his mother to do such a thing? But the boy didn't dare intervene. He couldn't let his mother know he had been spying on her. So he remained where he was and watched, his cock sticking up almost against his flat belly as his stepfather gently but firmly pushed his mother's head down.
Paula was in a state of very confused excitement. Her cunt hungered for the feel of a hard, thrusting cock, and she had that cock right in front of her, but Ray wanted her to lick it first. She believed this was extremely dirty. But the thought of doing it seemed to arouse her all the more.
Ray solved her confusion in the same way he had solved her uncertainty earlier about letting him lick her cunt. He simply made her do what he wanted. He applied stronger and stronger pressure against the back of her head, forcing her to bend lower until his cock was directly beneath her mouth.
A giddy thrill went through her as her lips came into contact with the big head of his up thrust cock, then skidded off as the shaft swayed. She was smelling him now-but to her surprise, she found the scent wasn't bad. In fact, she rather liked it.
She felt her heart thudding like a hammer as she stuck out her tongue and swiped it across her husband's fat, purplish-pink cockbead.
It's really not too bad at all! she thought.
Paula put her hand around the base of his cock to hold it straight up, and began licking it in earnest. Ray smiled as he watched her, Delightful sensations coursed through him, and he knew his new wife was going to be a great cocksucker after all.
Paula's tits hung down and swayed in mature fullness, bobbing together gently as she moved to and fo, licking all over his fat, tasty cockhead. Yes, it was tasty! She was surprised. And the scent which came from the aroused organ was really turning her on in a big way. Her thighs were very wet, and her cunt continued to drip like crazy.
Watching her closely as she licked his cockhead, Ray placed his hand over hers and moved his prick back and forth, rubbing the tip of it against. Paula's face and across her lapping tongue. He saw her lips open wider. She was ready to suck, he decided.
"Come on," Ray said softly but insistently. "Suck my cock, baby." He wiggled the huge cock between her soft, moist lips.
Paula's brain was reeling. She couldn't believe she really wanted to take the throbbing cock into her mouth, but that was exactly how she felt. And she didn't hesitate more than a moment before she opened her mouth wide and let the whole, fat cockhead, along with some of the shaft, glide in.
Ray's prick stuffed her mouth, depressed her tongue shockingly, and almost made her gag as it forged nearly into her throat. But she raised her head a little and saved herself from choking. She closed her teeth gently on the spongy cockhead and locked her lips around the back of the ridge. She sucked, getting a good strong taste of the flavorful cock.
She loved it.
"Bob your head, angel," Ray crooned. "Lick it while you suck. And don't suck too hard. Slow and steady does it."
Paula began to pump her encircling mouth up and down on Ray's hard, thrusting shaft, and she felt deliciously perverted. What a thrill this was? The nerve endings in her lips were highly stimulated by the gliding friction of his prick as the thick, slippery column pressed them outward, holding them open. The ridge of his cockhead offered a special stimulation to the sucking circle of her lips as they moved up and down repeatedly across it. She brought her tongue into more active play, fluttering and gilding the sensitive instrument against his cockhead.
She's turning into a real hot cocksucker! Ray thought, and he couldn't have been happier. This was what nearly every, man wanted from his wife. And far from degrading her in his eyes, it made him love her all the more, because it proved how much she loved him.
Ray gently moved his hips up and down, pumping his cock against her head thrusts, stroking his prick in and out through the soft, wet circle of her lips. He reached out and clutched her dangling tits, squeezing them and bouncing them gently on his palms.
Outside the window, Billy looked at Kathy, but neither of them said anything. What they had observed, and continued to observe, was amazing and shocking, but deliciously exciting at the same time.
Now that she had been introduced to the unique pleasure of giving head, Paula didn't want to stop. Ray's fat, spongy cockhead and the thick bone like shaft which supported it felt too good as they stretched her sucking lips and plunged deeply into her mouth.
However, the time came for Ray to make her stop. It was either that or let her finish him by mouth, which he didn't think she was quite ready to do.
Grasping his wife's head firmly between his hands, he lifted her off his cock. Paula's eyes were misty, and she obviously had become transported into a higher realm of sexual excitement than she ever had reached before.
As Ray guided her onto her back, she moaned, 'Fuck me. Oooooh, fuck me, darling!"
"Yes, sweet, I'm going to fuck you," he said as he mounted her, his immense cock projecting forward.
Paula reached eagerly for his cock, enclosing the hard, thick column in her hot grasp. She tilted the springy shaft down ward, direct into its tip to the flaring, wet folds of her cunt. Ray only had to give a slight nudge of his hips, and his cock glided deeply into her cunt until the throbbing shaft was completely enclosed by her moist, clinging warmth.
As her children stared-Kathy's young pussy dribbling profusely down her thighs, and Billy's prick thrusting hard against his pajamas-Paula hungrily heaved her hips against her husband's vigorous fucking strokes. Ray remained propped up on his arms so he could watch the play of passion on Paula's face and the rhythmic shaking of her tits as he fucked her with intense delight.
His firm cock sank repeatedly into her soft, yielding cunt, which wasn't so soft where it encircled him, clutching and twisting as she rose and fell in rhythm with his thrusts. Her tits shook; their up thrust nipples like buoys riding the rolling swells of the ocean. His belly slapped hers as their crotches churned together with a wet sucking sound.
Billy writhed as he watched them, and his youthful cock accidentally slipped through the fly of his pajamas to stand naked in the light that poured through the windows. Kathy didn't see his cock right away; she was too intent upon watching what was happening in the bedroom. Even Billy wasn't aware at first that his prick was exposed.
Paula whimpered sharply, then released a loud, ecstatic cry as she came. Her cunt spasmed around Ray's pumping cock. He speeded up, and his eyes rolled back in their sockets as he lunged blindly. His hard cock jerked in her convulsive embrace as his cum spurted, splashing into her welcoming cunt.
As the action on the bed came to a stop, Billy backed up from the window. It was then that Kathy saw, for the first time, her brother's erect cock, and she gasped. The cock was nearly as large as Ray's, but was lighter in color. The foreskin came down nearly to the end of his prick, with only the tip of Billy's pink, moist cockhead peeping out.
"Ooooh, Billy!" Kathy exclaimed. "Wowww!" Billy's first impulse was to cover up, but when he saw how excitedly his twin sister was looking at his cock, he got a wild new urge that would have been too shocking to consider until just a few minutes ago. But now his whole outlook on life and sex had changed.
"Do you like it, Kathy?" he asked huskily, his voice shaking. – "Y-yes!'' "Come on," he said. "Let's go into your room."
Kathy let him guide her in front of him, and they entered the bedroom. He closed the windows behind them and drew the, shades.
"Turn your light on," Billy said.
"Wh-what do you want to do?" Kathy asked nervously.
"You'll see. Turn on the light."
Quivering with excitement and apprehension, she felt her way to the bedside lamp and turned it on.
A soft glow splashed over the bed and the rug beside it.
"Let's take our clothes off," Billy said. "No!" his sister exclaimed, fear and shame asserting dominance now.
"I won't hurt you," he promised. "I just want to see what you look like. You're looking at me."
Was she ever! She could hardly tear her eyes away from his big, beautiful, stiff cock that was sticking up so fiercely.
It didn't seem right for them to undress together, but Kathy was so shaken by the acts she had just seen performed on her mother's bed, and by the feelings that were going through her, that she couldn't refuse. With trembling fingers, she lifted her nightie over her head and pulled down the panties that she wore underneath.
Billy, who was also naked by this time, stared at the breath-taking beauty of his sister's tits and downy-haired cunt mound. Her tits, while not very large, were shapely and firm. Their nipples were baby-pink and rigidly erect. The sparse hair of her pussy was as golden as the hair on her head.
Kathy was doing some staring, too. Her brother's hard-on seemed even more impressive now that he had no clothes on. It projected upward at a sharp angle, and now she could also see his balls, bunched up at the base of the shaft. He was really a man in every way! But she was mystified by the fact that his cockhead was partially covered by an outside skin, while Ray's cock wasn't. She couldn't resist asking Billy about this.
"How come you have that skin that comes down over it?" she inquired, pointing.
"That's called a foreskin," he said. "That's because I wasn't circumcised."
"Are most men… circumcised?" This fascinated Kathy. Somehow, she had never heard of it before.
"More are than aren't, I guess.''
"How come you aren't?"
"Because Mom didn't have them do it when I was born."
"Is it bad not to have it done?"
"I don't think it makes any difference." It pleased him to discuss his prick with his sister.
"But does that skin make it different when you… fuck?" she asked nervously.
Hearing her use the word "fuck" stimulated Billy even more. He hadn't thought she knew it, though if he had considered the matter he would have realized that a girl couldn't very well have gotten to be her age without haying heard the word many times at school.
"I can push the skin back," he told her, and he did it.
Kathy became even more excited as she watched his pink, moist cockhead surge into full view. Now he looked like Ray, except the head of Billy's cock was pinker.
"Can I touch it?" Kathy asked hesitantly.
"Sure," her brother replied' happily. "But let's lie down on your bed."
"Oh, no! That would be awful!" ''What's awful about it? We wouldn't really do anything. We'll just touch each other."
"Isn't that almost as bad as fucking?" Kathy asked.
"Cripes, no! You were touching yourself a little while ago. I saw you. And I touch myself down their lots of times."
"You do?"
"Sure. Lately something's been happening when I touch myself," he confided.
"Like what?"
"You'll see. Come on-lie down on the bed with me."
Kathy was too curious and weak right then to refuse this latest and most daring request by her brother. Though she continued to quiver with apprehension, she climbed onto the bed and stretched out on the covers.
Billy lay down on his back beside her, his cock wiggling stiffly in a way that continued to amaze his sister. As he settled himself, his cock projected backward above his lean belly.
"Does your thing hurt you when it's hard like that?" she asked.
''It's a cock,'' he said, "not a 'thing'." "I know."
"Then call it a cock."
"Oh, all right. Does your cock hurt you now?" "Naw, it feels great.'' "You like it to be hard like that?"
"Yeah. It feels much better hard than soft."
"I have something down here that gets hard, too," Kathy said and made a gesture toward her blonde-fuzzed cunt.
"Let me see," Billy said. He sat up and leaned over her.
Kathy's heart hammered wildly. She extended her hand toward his lap and said, "Let me touch you first."
At the first contact between her fingertips and his upthrust, hard cockshaft, she recoiled. But then she told herself she was being silly.
She wrapped her cool, slender, soft fingers around the rigid shaft and squeezed. She could feel her brother's blood throbbing in the organ. As she held her breath, she slid her small hand up onto the head of Billy's prick and squeezed the bulbous knob.
He groaned.
"You like that?" Kathy asked in a ragged voice.
"Yeah. It feels great!"
It pleased Kathy to know that she was capable of giving him pleasure. Also, the feel of his hard cock fascinated her. The shaft was so hard that it felt almost like bone with a thin layer of skin drawn over it, yet she could feel his vitality pounding inside. The cockhead was quite springy in contrast. It was also sticky and moist.
"Move your hand up and down on it," Billy pleaded, breathing hard. "That's what I do to myself sometimes."
"You mean like this?" Kathy asked, and began to stroke her encircling hand along the length of his cock, rubbing the foreskin back and forth across the ridge of his cockhead.
"Yeah!" Billy rasped. "Oh, shit, that's good!" ''Billy.."
"Well, it is," he panted. "Let me feel you, too."
Kathy parted her legs as Billy reached across to touch her, and his fingertips explored her enticing little pussy. The dainty folds of flesh were very slick and soft. But she was right about having something hard down there, also. It felt like a little pea and was located in the folds at the very top of her slit. When he began to touch it, Kathy gasped with delight.
"What do you… call that?" he asked as she continued to stroke his cock up and down.
"It's my clitoris," she told him. "Rub it. Pinch it. That freaks me out!"
Billy rubbed the slick little pea as she had requested, and she stroked his cock all the harder. They writhed together on the bed as waves of sensual pleasure coursed through their hat young bodies.
Kathy thought of her mother getting licked between her legs by Mr. Simpson, and she tried to imagine how that would feel. She also though of her mother getting Mr. Simpson's long, stiff cock shoved into her, and she daydreamed for a moment, placing herself, rather than her mother, on the bed with the older man.
Billy too was playing mental games while Kathy stroked his cock. He kept visualizing his mother going down on his stepfather's prick, and he imagined her going down on him, instead. Then he thought of one of his teachers, who was a pretty young woman, going down on him. His mind flitted to other girls-girls in his classes at school- and he imagined them sucking his cock and letting him fuck them.
Kathy's cool little hand kept stroking his cock, and Billy kept tickling her clit. Finally he knew that the thing that had been happening to him lately- the thing he had mentioned to his sister-was going to happen again. Right now.
He groaned, arched upward, and enjoyed a magnificent sensation as his young cock suddenly spewed forth a spurt of thick whitish cream. Kathy gasped when this happened and jerked her hand away from him, but his prick kept spurting and twitching. The cum splattered against his belly, making a pool there, and Kathy stared at it in fear and amazement.
"Wh-what's that?" she asked after he had calmed down. "What happened?" She was afraid she may have hurt her brother in some way.
"It's… all right," he said, breathing heavily. "That's what I was telling you about. Oh, man, I feel good!"
Kathy didn't know what to make of it, and she didn't feel very good at all. She had felt wonderful a few moments ago, while Billy was rubbing her clit. It had seemed that she was building up to something really fine. Then that awful eruption from Billy's cock had startled her, and he had stopped rubbing her cunt. Now she felt nervous and uptight.
The stuff that had came out of Billy smelled funny. Not bad, really, but kind of strong and strange,
"What is that?" Kathy asked, staring at the cum on his belly.
"It's what makes babies," Billy said. "It's called semen. Didn't you ever study about that in school?"
"Oh. Yeah, I guess I did."
Billy looked closely at his sister. "How do you feel?"
"I don't know. Not so good, I guess."
"'What's the matter?"
Kathy's mood suddenly changed, and she became hostile. "Oh, don't ask me things. I don't want to talk any more. Go back to your room."
"But, Kathy-"
"Go back to your room right away!" she demanded, her voice rising.
"Okay… okay," Billy grumbled, and got off the bed.
He also felt uneasy about what they had done, now that it was over. He put on his pajamas and Kathy slid under the covers.
Just before leaving the room, Billy warned, "Don't tell Mom what we did."
"Mom!" Kathy said scornfully. "After the way she carried on with that man, she's got no right to bug us about anything."
"Just the same, don't tell her."
Kathy's tone softened. "Don't worry, I won't."
After her brother had gone, she turned out the lamp. She felt miserable, both mentally and physically. She lay there for a long while before finally falling asleep.