“What are you doing, brother?”

He dropped his hands to his sides and stopped moving. His sister had caught him masturbating in bed!

“Brother? I heard you.”

He didn’t move. Why, oh why, did they have to share a room? Yes, it had a curtain running down the middle for privacy, but now that he was sixteen and her fifteen, they should have separate rooms! He knew why, though; his father was the only one who earned a salary, their mother staying home to school them, so they could only afford this two bedroom apartment. He thought that maybe they were holding out with just two bedrooms for a couple more years until he went off to college or the military, or whatever, but he was a teenage boy! He had to relieve the pressure of his hormones in private.

“Hmp.”

He waited until his sister’s breathing became regular before he started again. Now that the Coronavirus lockdown was in its tenth month, he had no real inspiration to whack off to, other than women on TV or online. He struggled to remember a video from a pornographic site he had managed to reach a couple weeks ago that hadn’t yet been blocked by his parents’ “nanny” software; it had been unreachable the next day. His slim cock hardened again as he thought about the busty blonde stepsister in the video, spying on her stepbrother masturbating in the shower as she pleasured herself, and after she was caught...

“Aha!”

A flashlight shone on him as his sister slipped around the curtain. There would be no doubt what he had been doing, with his comforter tenting up and down repeatedly. “Shit! Sis...”

She turned off the flashlight and he felt her sit on his bed. “There’s nothing wrong with it, bro. I do it too, y’know.”

He did know. Sometimes after he orgasmed, he heard her gasping on the other side of the curtain. It made him feel weird when that happened, and he had to plug his ears so that he could go to sleep.

“Can I watch?”

His eyes widened. “Wa ... watch? I ... no! Go back to your bed, sis.”

She shifted. “Pleeease? I’ll let you watch me afterward.”

He almost rebuked her, then, telling her in no uncertain terms that this was unacceptable, and to return to her own bed or he would tell their parents, when a familiar noise started up on the other side of his wall. A soft thumping, and a female voice, “Oh! Oh! Yes! Harder...” Their parents were having sex again.

His cock lurched. Muffled like that, the voice could be any woman being pleasured.

“Mmn...” He felt his sister shift position on his bed again. He felt something bump his penis through the covers.

“Hey!” he hissed at her.

“Oh, sorry,” she replied, and her extremity retreated.

He reached up and turned his side table lamp on. A light the intensity of the sun blinded him, and he blinked until it faded to the normal 40 watts of illumination. He saw that his sister was sitting spread-legged near the foot of his twin sized bed. When she had done that, her foot must have extended between his legs and brushed his crotch. She was wearing a long t-shirt, but her current position had bunched it up around her hips. Her hands were between her legs, keeping the front of the t-shirt pulled down, and her face was flushed.

He considered his sister. Not busty like the blonde from the pornographic video, and not even a blonde, with her brown hair, so much like his and their father’s. She was pretty, though, and showing off some nice, slim legs...

He shook his head. His penis wasn’t getting soft, which meant that it was holding some of the blood that would otherwise have helped his brain to think straight. “Why do you want to watch me?”

She nibbled her lower lip, her eyes down. “We both masturbate, and we hide it from each other. Wouldn’t it be better if we didn’t have to hide?” She locked her eyes to his, and he was transfixed by the intensity of her gaze. He had never seen this look on her face before. His penis twitched again.

The muffled moans continued, “Ohh ... from behind ... yessss...” Thump thump thump...

“Okay.”

His sister’s eyes widened in delight. “Yes!” she exclaimed softly and waited.

He took a breath and then pushed his covers off. He was naked from the waist down, having lowered his boxers before he started. He heard his sister’s breath catch at the sight of his hard penis.

“Wow...” she breathed.

He felt a little chuffed at that. She was the first person to see his penis since he had hit puberty, and he didn’t know if his erection was normal or small. Pornography, even the little he had seen, certainly didn’t provide a standard set for comparison. He grasped his member and started to stroke.

His sister kept her eyes fastened on it, her mouth slightly open as he pleasured himself. He didn’t want to keep watching his sister as he masturbated, so he lay back, closed his eyes, and replayed that pornographic video in his mind’s eye.

In it, the busty blonde pushed the door of the bathroom open and saw the slim, athletic form of her stepbrother through the foggy glass of the shower door as he masturbated. She unzipped her tight cut-offs and shoved her hand inside in order to pleasure herself as she watched.

He wondered what a real vagina felt like. The blonde’s looked amazing later in the video.

“Unhh!”

“Oh! Yes! Yes!”

Upon hearing his father grunt through the wall as he filled their mother’s vagina with his semen, and her crying out in pleasure in response, the brother started to orgasm himself. He grunted as silently as possible as his cum shot high in the air and splashed down upon his chest. Finally, he squoze the last drops from his shaft and relaxed.

“That ... was ... amazing!”

He opened his eyes. He had almost forgotten that his sister was watching! He suddenly felt very self conscious, and went to pull up the covers.

“Don’t you have to clean that up?”

Yes, of course he did. He let go and reached for the tissue box on his side table. His sister continued to watch, wide-eyed, as he sopped up the silky white mess. Finally, he tossed the sodden tissues into his waste basket, pulled up his covers, and lay back, finally relaxed and ready for sleep.

“Okay, my turn.”

He looked back down at his sister as she reached between her legs. Was she really going to... ?

One hand slipped under her t-shirt while the other continued to hold it down, hiding her vagina from his sight. Her hard nipples poked through her shirt. She moaned as she touched herself and closed her own eyes.

“That’s not fair.”

She opened her eyes and looked at her brother, who had sat back up to regard her. “Not fair?” she asked.

“You saw my penis,” he explained. “I should be able to see your vagina.”

She considered for a moment, and then, nodding, she pulled her t-shirt up enough so that he could see between her legs.

He noted some light brown hair surrounding a puffy, vertical slit. He narrowed his eyes. This wasn’t like the woman’s in the pornographic video, whose vaginal lips had been spread open, showing a pink entrance that looked wide enough to accommodate her “stepbrother’s” penis. His sister’s seemed closed-off, unwelcoming.

Her face red with embarrassment, she moved one finger to the prominent little bud near the top of that slit and rubbed it. She moved her other hand up to her hard nipples to caress and tweak them through her t-shirt.

She closed her eyes as she thought about what her brother had just done, his hand sliding up and down his beautiful hard penis. His face had been screwed up in concentration, and then as he reached his release, his features had softened, transforming into a beatific configuration she had never seen before as he released his essence.

“Oh! Oh!” she cried out as she came quickly to the memory. Her slim teenage body shook as pleasure blossomed from her clitoris, the feeling somehow amplifying, connected to her hard nipples and as she tweaked and rubbed them.

“Wow!”

She looked up at her brother watching her. Suddenly embarrassed, she pulled her t-shirt back down to cover her vagina.

“Um...” he said.

“Yeah...” she replied.

“I’m hard again.” Her brother pulled his covers off to punctuate his statement.

“Oh.”

Bang bang! “Go to sleep, you two!” That had been their father on the other side of the wall.

His sister dashed back to her bed as he reached over to turn the lamp off.

“G’nite sis.”

“G’nite bro.”

He thought that what they had done the previous night would change their relationship, but on the next day everything was normal. It was a weekend, so she stayed in the bedroom doing online things with old church friends that she hadn’t seen in person in months while he played video games in the living room. When they were called to lunch they ate their grilled cheese sandwiches and tomato soup without any weird looks between them.

That evening, they watched TV and movies with their parents, just like they usually did, and then they went to bed.

After they lay there a bit, she whispered out, “You wanna do it again?”

He really did. Not having to hide it from each other was a wonderful thing. “Yeah ... I’ll come over there so we’re farther from Mom and Dad’s room.”

“Good idea.”

He rose and went over to her bed while she turned her bedside lamp on. Like his, her bed was a twin size so there wasn’t a lot of room; he sat below her legs. “I was thinking,” he said, “if I go first and then you, I’ll get hard again, and then we’ll never get to sleep. So, how about you go first and then me?”

She was pleased that her masturbating excited him enough to get hard again, but she had another idea. “How about we both do it at the same time?” Then she pushed her covers aside and pulled her t-shirt up to reveal her cute little vagina.

“Oh ... yeah,” He pulled his boxers off, revealing his very hard and ready erection.

She spread her legs and reached down to play with her pleasure button, but couldn’t get a very good look at his penis while he was sitting sideways with his feet on the floor. “I can’t see ... can you turn toward me?”

He sat further up onto the bed and turned to her, but then he couldn’t see her vagina very well. He got up onto his knees and moved forward, between her legs.

“Yeahhh...” she moaned as she lay her head back onto her pillow. She had a very good view of him sliding his hand up and down his hard penis as it was pointing at her. Yes, she thought, this felt right.

He had originally meant to just think about the pornographic video again, but there was a real, live vagina, right there in front of him! As long as he didn’t look at his sister’s face, he could pretend it was any woman’s. His hand skimmed faster along his erection.

She was using her other hand to rub her nipples through her shirt, gasping as she watched him masturbate.

“Um ... do you think you could pull your shirt up all the way?” he asked. He hoped he wasn’t pushing this too far.

Apparently he wasn’t, as she rose to her elbows and pulled her shirt right off. “You too,” she commanded, and then, very quickly, they were both naked.

He watched as she returned to rubbing and tweaking her nipples, no longer limited by her shirt. These were the first real breasts he had ever seen, small compared to the women in porn, but beautiful. He had seen them pushing her shirts out, with and without a bra, but seeing them like this was amazing.

He realized that he was already getting close. He also realized that he had no idea where to spurt. He was between his sister’s legs, and he didn’t want to lose his orgasmic momentum. She had closed her eyes and was breathing heavily, her finger moving fast on her clit.

He grunted and loosed his sperm, pointing his penis right at her clitoris.

She heard him grunt and then felt hot liquid splash on her clitoris, hand, and all around her vagina. She had been so close to her own orgasm that this didn’t just push her over the edge, it shot her past it like a rocket ship!

“OhhhHHHH!” she cried out softly, orgasming hard, her hips instinctively rising off of the bed as her fingers rubbed furiously at her clitoris. With this new angle, the next splash of his semen hit directly on the tight split between her vaginal lips. The feeling of another dollop of hot cum hitting her privates sent her into a second orgasmic wave. “Uhh ... uhh ... uhh...” she moaned, her slim body shaking, overwhelmed with pleasure at this novel, forbidden sensation.

“Ohh wow...” he gasped as he fell back on his heels, utterly spent. That had been a strong one!

Finally, she came down from the most powerful orgasm of her young life and relaxed, her legs splayed, a silly grin on her face.

“Shit...” her brother said as he went to grab the box of tissues from her side table. “I’m sorry, sis! I didn’t know where to shoot.” He held out the box.

“It’s fiiinne...” she breathed as she grabbed a couple of tissues and started to dab up the mess. She cleaned up the white gobs on her pubes and perineum, and what had dripped under her butt, but with her angle of view she didn’t notice the pearlescent liquid shining between her vaginal lips. She pulled her covers up while her brother went back to his bed.

“G’nite bro.”

“G’nite sis.”

For the rest of the night, her brother’s sperm did their best to slip between her vaginal lips. The few that succeeded began their preprogrammed way deeper inside the virginal teen girl.

His sister had resolved not to let what they were doing mess up their relationship. They had been close growing up, only a year apart in age and their own best friends, though once her brother had become a teenager, their relationship had changed and he started treating her more like an annoying kid. In the last year or so, though, they had started to get along again as she likewise became more mature.

She, however, was not technical-minded, and therefore did not have the same access to inspirational online media that he did when masturbating. While he had found the occasional unblocked pornographic video on his tablet, she only had music videos, TV, and movies, and none of those were remotely sexual thanks to the efforts of her conservative parents. When she awoke one night to hear her brother masturbating, she had been excited in a way like never before, and her first orgasm, a little after he had finished and fallen asleep, opened her eyes to a new source of excitement.

On Sunday, they virtually attended church via streaming video. It just wasn’t the same thanks to the pandemic, but privately the kids agreed that it was nicer to not have to dress up and say hello to a bunch of people they didn’t really know. They barely went out prior to the lockdown, since their mother homeschooled them, so it was just one more place they didn’t go, and they didn’t miss it.

That night began much as the previous, with her brother kneeling between her legs as they masturbated. As she got herself close to orgasm, though, her brother touched the tip of his penis to her vaginal lips as he stroked himself. Her eyes flew open. “No! We can’t have sex!” she hissed.

He pulled back and she kept her eyes on him until he came, blasting her clit and vagina with his sperm again and giving her another massive orgasm at the sensation of his hot semen splashing onto her privates. She fell asleep, again unaware that a tiny amount of her brother’s sperm was making its way deeper inside her.

Their mother got them up bright and early for their lessons. The woman had been a teacher before marrying their father, but once the kids were born she had naturally stayed home with them while he continued to work. Once his son got old enough to go to school, the man insisted that his wife homeschool the boy, and then a year later, the girl.

One thing that was never taught to the kids was sex education, so they had no idea how babies were made. When they had asked, their mother talked about marriage and love. The kids naturally thought that you couldn’t get pregnant, however that happened, without getting married first.

That night, the sister asked, “What if I masturbate you, and you me?” That way, she figured, she’d make sure that her brother didn’t try to have sex with her. She had to save herself for marriage!

Her brother was all for it, and he got right up between her legs, his penis over her stomach, as she lay back on her bed. She took his erection in her hand, marveling at the feel of the hard shaft underneath the strangely shifty skin before she started to stroke.

“That feels really good, sis,” her brother whispered as he reached down to touch her vagina. He was a bit awkward at first, but she directed his fingers to her clitoris and then lay back again, getting used to stroking his cock as she felt the pleasure he was giving her flowering between her legs.

One of his fingers tried to slip between her vaginal lips but she reached down and grabbed his hand. “No penetration,” she stated. That was too much like sex, and that was a firm line for her.

Soon her brother was rubbing her clitoris just right, and he also reached up to palm one of her breasts. It felt amazing when someone else did it! She figured it was like trying to tickle yourself; you just can’t. Alone, she would never be able to make herself feel like she currently felt with her brother’s hands on her.

She was getting close. It was going to be a big one!

“I’m gonna shoot, sis,” her brother warned.

She pushed him back a little as she stroked so that the tip of his cock was aiming right at her vagina and closed her eyes. Almost, almost...

As her stroking pushed him over the edge, he thrust his hips forward a little so that the tip of his penis touched where her vaginal lips came together just below her clitoris. She had no chance to correct the position as his first blast of dangerous, sperm-laded semen shot into the small gap.

“Unhh!” she cried out as she felt the hot pressure of that spurt ricochet off the top of the entrance to her vagina. Her orgasm crashed down upon her like a tidal wave, and she arched her hips while continuing to stroke her brother’s cock, causing the tip of it to slide down, along her slit. This lined it up with her vaginal entrance proper, and his next spurt shot between her lips and spattered her hymen, the result being some of her brother’s seed slipping through that porous barrier. She felt a spreading warmth inside her, where nothing had ever touched before, and this new sensation redoubled her orgasm. “Oh-hhhh!”