Summer Inside His Sister

Neither of them dared to breathe, let alone move. Both Ethan and Katie remained frozen, looking at each other, trepidation painted clearly on their young faces. Neither of them dared so much as a glance at their mother, who was staring at her son with a quizzical expression. Several long, heavy seconds have passed before any sound disturbed the eerie silence.

"Well! I'm sure there is a perfectly valid explanation why my kids are walking around naked, and..."

The mother's voice faltered, and she bit her lip as she felt a bunch of confused emotions flow through her, one after another.

"Uhm, we were just... I mean..."

"Stop it, Ethan," his sister said soberly. "We aren't going to pretend this isn't exactly what it looks like... Mom? Ethan and I are having sex."

Mom's lips quivered. She looked at both her children, and saw that there was not a stitch of clothing between them. It was completely surreal.

"How long?..."

"Just today," Katie jumped to answer. "It... sort of happened."

And then it happened again, and again, and again... That's what she thought in her head, but of course Katie was smart enough not to say it out loud.

The situation was awkward enough already, with both her and Ethan standing in the living room and kitchen, naked, and still very much covered in liquid evidence of their recent coupling. Katie was strategically hidden behind the counters, so a hand on her breasts was enough to stop her from flaunting her intimate parts. But Ethan was right there in the open, and clearly too shocked to even think about covering his sizeable dick. The monstrous thing was still at half-mast, and Katie had a hard time trying not to stare at its stubborn tumescence.

"It happened," her mother repeated blandly. "Just like that?"

"I... I walked on him masturbating," she said, deciding that in these circumstances, the fact that her brother was jacking off wasn't exactly shocking news anymore, "and I, uhm, dared him to finish with me watching..."

Katie's mother raised an eyebrow, but otherwise didn't do much to acknowledge her daughter's explanation. "Ethan? What do you have to say?"

"I, uhm, well... I don't have anything to add. Mom," he tried to weasel out. "Katie's telling the truth!"

To everyone's surprise, Mom let out a hearty chuckle. "So! My son is finally admitting that it is not 'yogurt' that I would sometimes find dried up on his desk," she said in obvious amusement. "All it took was me discovering that he's been having sex with his sister! Lovely. Anything else you kids want to share?"

The siblings exchanged confused looks, unsure what else to say. They still had no idea what their mom thought about this, the two of them engaging in incest. She hasn't yelled at them at least, or told them to move out, so perhaps all wasn't lost yet?... Come what may, Katie figured that she and Ethan should at least present their case.

"Mom, look... We are just having some fun. I'm not gonna fall in love with Ethan -- more than I already love him, that is -- or marry him, or heaven forbid have his babies!" Katie shuddered at the very thought. "We were just bored, and horny. I'm on the pill, and Ethan... uhm... hasn't done it before, so nothing's bad gonna happen, Mom."

Katie's mom shook her head, crossing hands under her breasts, "Honey, this is called incest. Regardless of what I think about it, the law says it should be illegal."

"No one has to know, Mom," Ethan chimed in, finally having the presence of mind to cover his exposed crotch. "Like Katie said, we aren't dating or anything... We are still just brother and sister."

"...who also happen to sleep with each other, eh?" his mom said, and scoffed lightly. "Isn't that wrong?"

"We don't care --" they both started, then realized they were speaking simultaneously. "We don't care what people think, Mom," Katie continued, smiling at Ethan who was evidently of the same mind. "We aren't hurting anyone, and we have nothing to be ashamed of. I wish you could see it this way, too..."

For the first time, their mom smiled. "I understand that, Katie. I can't say that I'm very enthusiastic about you engaging in this sort of thing, but you should do whatever makes you happy. Honestly..." she started, then dropped the thought. "Nah, never mind."

"What, Mom?" Katie insisted. "We want to know what you think..."

Mom's smile turned into more of a smirk. "Well, if you insist... I was gonna say that I am not _entirely_ surprised that this happened. For one, Ethan has been looking at you like a snack from the very moment you stepped into the house."

"Mom!" The boy cried in embarrassment. "...You noticed?"

She rolled her eyes. "I am not as oblivious as you think I am, young man. Your sister is a gorgeous woman, but that was more than brotherly appreciation of her beauty. Sometimes, you were just blatantly staring, you know..."

Ethan gasped, blushing as he hung his head in shame; Katie couldn't help but let out a girlish giggle.

"And you, young 'lady'," her mom turned to her, and actually used air quotes to emphasize her point, "you are even more boy-crazy than I thought! Your own brother? Really?"

It was now Katie whose face went beet-red. She fidgeted in place, staring at the cutting board with condiments for the still-unfinished sandwiches she'd been making.

"In all honesty, though," her mom spoke again, her voice lower and a bit quieter, "I think it might actually be good for the boy. At least he won't be jerking off so much."

"MOM!!!"

She laughed. "What? Have I said anything that is not true?"

Feeling very seen, Ethan used a second hand to cover his chubby penis, then skipped behind the counter next to Katie. His sister smiled at her lover, realizing, to her astonishment, that even in this tense situation her pussy tingled from the mere presence of her studly brother. She would love for him to just bend her over the counter and fuck her right then and there, but that was obviously not an option at the moment.

"Well..." Katie decided to risk a more explicit admission. "If that's not saying too much, I'm kinda trying to teach him stuff as we go along... Sex stuff, I mean. He's been a very fast learner so far!"

"Oh, was he now?" said her amused mom. "Looks like you found the one topic, other than video games, that actually interests him!"

"Oh my god! YOU TWO!" Ethan cried in exasperation, which only made both of them laugh. The tension was definitely abating, and Katie was starting to think that maybe her summer plans weren't completely ruined after all. Mom seemed cool enough with the two of them fucking, and it looked like it shouldn't be much of a problem if they continued... Question was, could it mean she would tolerate them doing it even when she was at home?

"Mom, speaking of Ethan's, ahem, education," Katie chanced. "I made him a promise... He was to have an unrestricted access to my body, whenever he wanted me. I'd stay nude at all times, to get him more accustomed to what a naked girl looks like. He was supposed to stay naked, too. Now I'm wondering if this is still on the table..."

Mom's eyes went wide. "You kids want to be nudists now?"

"Uhm, yeah... Although not quite. This would definitely be *sexual* nudity, Mom. That's the whole point!"

"Huh..." Her mother pondered this for a moment, glancing at her already nude children. "I don't mind you going around the house like this, though you better put some towels when you sit somewhere," she said with a chuckle. "But you're saying you also want to have sex wherever the feeling strikes you, and I just don't know about that... What if I'm in the room, too?"

What the hell? Katie was astonished that Mom didn't simply shoot her down instantly! Her objections were completely reasonable, of course, but Katie was now too excited about the idea of complete sexual freedom, for her and her brother, to let go of it so easily.

"Would it bother you, Mom?"

"To see my children fuck?" she said the naughty word so casually. "That's not a question a mother is supposed to think about, Katie..."

"Okay, that's fair. How about you just tell us to get lost if we get too distracting?"

Katie feared that she had definitely crossed the line, but her mother just laughed. "Right, maybe I'll tell you lovebirds to go get a room," she said in jest, "and as long as it works, then perhaps..." she trailed off, thinking about it some more. A few long seconds passed until she sighed and finally said, "Okay, I can't believe I'm actually agreeing to this, but if that's how you kids want to, uh, explore your sexuality, then go off I guess!"

"No way!" Ethan jumped in. "You are the best mom ever!"

"The absolute best!" Katie agreed. "In the whole world!"

"Alright, alright! Let's see if I don't regret it," she said with a weak smile, and sighed again. "Now, since you dropped this absolute bombshell on me today, I think it's only fair that you kids should take care of dinner. I'll be in my office if you need me."

With that, she left the sibling couple and walked away. Just before she's gone out of sight, she turned around and said with a cheeky grin, "Just make sure you wipe the counters when you're done."

***

A minute after their mom left, Ethan and Katie were still in a state of shock. They stared at the distance, uncertain what to make of everything that happened just now. Katie in particular couldn't believe that her conceit actually worked. She and her brother now had a free pass to fuck each other to their heart's content!

"You were right, sis," Ethan said, not actually looking at Katie. "Mom is just really, really cool."

His sister giggled. "I know! Honestly, though, this went way better than I expected, like, by far," she admitted, her eyes soon wandering down to her brother's prominent crotch. "Aww, you softened a little... Want me to fix that?"

"Wow, Katie! Are you always this horny?"

"I said I can be very demanding," she purred, "but I think it's mostly your fault, brother. Your cock is all I can think about now!"

He teased her, "So that's why I didn't get my sandwich."

"Shit, you're right," Katie agreed, restraining her impulses. "We really need to fix some dinner. The last thing we want now is for Mom to have second thoughts about all this!"

With her brother to help her around the kitchen, along with her laptop to look up a suitable recipe on the internet, Katie managed to parlay the unfinished sandwiches into a decent-looking bread lasagna. Less than half an hour later, it was already simmering in the oven, allowing them enough time to turn their attention back to other matters...

"Fuck me harder, Ethan! Oh god... Yes, deeper! I wanna feel... every inch..."

Bracing against the counter, Katie was pushing her hips against her brother, eagerly meeting his rapid advances into her sopping wet snatch. Ethan was railing her from behind, driving his hard cock deep into his sister's tight pussy, heavy balls slapping against her sleek thighs. He grunted with each thrust; his muscles were sore from all the physical effort, but he was determined to give his sister the pounding that she clearly loved.

This was the first time they were fucking outside of Ethan's bedroom. It excited him to no end, to have sex with his hot sister, anywhere they liked and at the drop of a hat! It was intoxicating to think that Katie was now his to take on a whim, just like she could jump on his cock whenever he least expected it.

Both siblings knew they'd be (ab)using this privilege a lot in the coming days and weeks. And it was all thanks to their incredibly cool mom, who not only accepted their incestuous relations, but also allowed the horny teenagers to have sex all over the house!

"Uggggh!... I'm coming, Katie! Your brother's cumming in your pussy!"

She moaned throatily, feeling Ethan's massive cock unload in her vaginal hole for yet another time today. It filled her completely, again, and before long there were trails of cum leaking down her inner thighs. Mindful of the possible mess, she reached for a paper towel and tried to wipe herself clean, only for more of her brother's semen to trickle down from her flooded young pussy. Laughing at her predicament, she excused herself to the bathroom, leaving Ethan to take their baked dish out of the oven.

"Smells delicious," he heard his mother's voice, and he turned around to see her smiling. "What is it?"

"Some kind of lasagna, I guess... Katie found the recipe."

Ethan's mom looked at him from under the eyelashes. "I heard you just now."

"You -- oh," he said sheepishly. "Sorry. We'll try to be more quiet."

She shook her head, then sat on a bar stool on the other side of the kitchen counter. "I wonder... Was it mainly because she's your sister? Or did it happen simply because she is young, hot and willing?"

Ethan blinked, surprised that his mother would speak to him so candidly. "Uhm..."

"You don't have to answer, of course," she said, glancing sideways. "I'm just curious whether my son grew up to be like most teenagers, who'd jump any pretty girl who smiled at them nicely..."

He felt his cheeks getting warm, and it wasn't the heat from the oven. "I... well, you know..."

"Oh, don't get so flustered! Nothing wrong with doing what the nature intended," she said reassuringly, and Ethan thought she even saw her wink. "In your case, I'd say it's about time. Sister or not, this girl seems to be the exact right kind of 'bad influence' that a boy like you could use..."

Not entirely sure what his mom meant, Ethan simply spoke his heart. "I love Katie, as a sister. But it's like, impossible not to notice how hot she is! When she asked me if I would like to, uh, have sex with her, I just couldn't resist..."

There was a brief silence between them, until Katie's voice could be heard down the hall. "Did you get that lasagna out of -- Oh, hi Mom..."

"Hey," her mother said, smiling, yet looking over Katie's naked form in a way that made the girl blush. "Seems like you guys have cooked us something really good. And you cleaned up your mess, too! Very nice..."

"Uh, thanks Mom," said Katie. "Please, take a seat!"

Understandably, dinner was a little awkward. Ethan kept glancing at his sister's exposed breasts, getting caught by his mom and feeling embarrassed about it, then realizing he shouldn't really feel like that anymore, then somehow forgetting it when Mom noticed him stare at Katie's chest again. After a few more rounds like this, Katie caught on to the fact that both of them were essentially looking at her boobs most of the time, so she made a show out of sitting upright and puffing her chest as she giggled.

"Poor Ethan has trouble concentrating on his food!" said Mom, chuckling. "What have you done, Katie? The boy needs to eat if he is to keep up with you!"

"Oh, don't worry Mom! He's been keeping up just fine, for the most part," the girl said, teasing her brother, then rubbing his shoulder in reassurance. "He does not disappoint where it matters, I can tell you this much!"

"Really? How many times?"

"Mom!" the siblings cried in unison.

"Nuh-uh," their mom didn't relent. "If you are going to fuck like rabbits wherever you want, then the least you can do is indulge your old mother's morbid curiosity. So?"

Ethan protested, "Mom, you are not old!"

"Shush, bro, I'm counting," Katie chided him. "Ugh, six times maybe?... We kind of just rolled through the day, so I wasn't really paying attention. Then we got hungry and came downstairs, and... well..."

Katie's mom looked at her with raised eyebrows, and threw the same glance at Ethan. Shocking both of them, she then bent down and looked under the table, chuckling as she spied her son's latent erection. "Oh my! And it seems my boy isn't even done yet," she said, her voice betraying a hint of pride. "Someone needs to take care of this, and soon!"

Katie wasn't sure, but there was something about the way Mom said it that implied it might not have been his sister that she had in mind...

"Well, that can't be me!" Ethan said with a laugh. "It is forbidden for me to jack off; Katie's orders!"

"Yeah! Don't even think about it, brother," his sister said, reaching under the table to stroke his rock-solid hard-on. "This is *my* job now! Finish up, and we can go upstairs..."

"Absolutely not," their mom interrupted, sporting an almost mischievous smirk. "Ethan needs to put some meat on his frame. He should have seconds."

"But Mooom!" Katie whined, for a moment sounding like a petulant child. "I want Ethan to.... ugh, you know!"

"To fuck you? Yes, honey, you can use adult language with me," her mom said, still smirking. "And I don't understand what's the problem. Wasn't this the whole idea? Any time, any place?..."

Was this a challenge? It sure felt like one to Katie! Could she actually go through with it, like she had promised, and allow Ethan to use her body even with their mother sitting right across the table?... Fucking her brother was one thing, but doing it right in front of Mom was on an entirely different level! She realized she could be in over her head, but that didn't mean she wouldn't swim deeper, right?

"Scoot away with your chair, bro," she commanded, waiting for Ethan's hard cock to emerge from behind the tablecloth. The moment it popped, Katie stood up and straddled her surprised brother, holding on to his shoulders as she sank onto his rigid shaft. When the pleasurable gasp died on her lips (as did the more astonished one on her mother's), she twisted her body to the side and pointed at Ethan's unfinished meal with an immensely satisfied grin. "Bon appetit, dear brother! You'll be okay eating and fucking me, right?"

"You are incorrigible!" Katie's mom sighed in exasperation, her eyes glued to the mating couple. But she wasn't even sure she believed her eyes; she just snorted a laugh at the ridiculousness of the whole situation. "Alright, this works. Just don't break the chair, okay?... Kids?"

They didn't seem to hear her, though. Ethan and Katie were really fucking now, largely oblivious to their surroundings. Funnily enough, it was his sister who fed Ethan bites of lasagna, using her impressive flexibility to scoop up the food while she was grinding against her brother's crotch. He didn't have to do more than simply chew -- and feast his hands upon his sister's sleek body, of course.

Their mother eventually shook her head, smiled weakly to herself again, and left the kids to enjoy their impromptu encounter.

At least doing the dishes would be on them, too.

***

When Linda woke up in the morning, she thought she just had a really weird dream. She remembered coming back from work, but for some reason her children were naked?... And they were eating dinner, and something happened there... She wasn't exactly sure what.

"Oh god, Ethan!... Yes! Just like that! Fuck me, brother, fuck me, fuck me, fuck meeeeeee!!!"

...Oh.

Ooooh!

Right -- now she remembered.

Ethan and Katie were having sex. They were having sex *with each other*. They'd been bored and horny, and apparently it just sort of... happened. Like any mother would, Linda wasn't exactly pleased to learn about this. But like few mothers would, she decided she wasn't going to prohibit it. After all, she trusted them. They were adult enough, and 'incest' was just a silly word. They were simply having fun, and no one was getting hurt by it. So, she decided she'd just let them be.

But then Katie kept pushing.

The two of them wanted to stay nude, at all times, including around their mother. And apparently, they had this agreement that they were both fair game for each other: if one of them wanted it, then they would just start fucking immediately, right on the spot!

Initially, this seemed insane to her, but Linda believed in freedom above all, so it wasn't long before she started looking for excuses to justify this arrangement. They were young; their hormones were raging; Katie has always been promiscuous; Ethan was having sex for the first time and he needed a lot of practice; it was summer; they wanted to experiment -- lots of good, valid reasons.