Summer Inside His Sister Pt. 03

Friday started for Ethan the same way his past few days did. He woke up with a parched throat, a dull ache in almost every muscle in his body, and of course, a huge hard-on. Lolling his tongue around, in the vain hope to make his mouth feel less like Mojave desert, he made a mental note to haul a few more gallon-jugs of water to his bedroom. Hydration was important, especially during long stretches of physical activity; and lately, Ethan had been getting more exercise than he ever did in the entire eighteen years of his life.

Raising his head slightly, he looked around the bed and smiled. Next to him was his beautiful older sister Katie, happily snoring away as she lay on her stomach with the legs spread out. Ethan could just about spy the puffy purple lips of her labia, along with a thin streak of dried cum connecting it with the crusty puddle beneath.

This has been his final load from yesterday, deposited inside his sister's pussy only moments before they both drifted to blissful sleep. Seeing her like this, naked and leaking his own seed, made Ethan's cock twitch with desire as he recalled their last steamy session of the day before.

He and Katie had been having sex for several days now. It started about a week into the summer break, shortly after Katie came back home following her first year in college. The siblings' incestuous liaison wasn't at all a secret: the very first day it began, they were actually discovered in the act by their mother.

Thankfully, she was open-minded enough to realize there was really nothing wrong with it. It was merely her kids acting on their strong, physical attraction to each other. Being a good mother, she wanted to support their choices, regardless of what the wider society would think about them. She therefore fully approved of their taboo relationship, and even went so far as to accommodate the highly unusual way in which they wanted to conduct it.

The arrangement was originally Katie's suggestion, but it was hardly surprising that Ethan agreed to it in a heartbeat. Though it was ostensibly for his benefit, as a recent virgin who needed to learn more about sex, his sister was equally excited about him keeping his part of the deal.

To put it simply, the horny siblings agreed to remain nude at all times, allowing themselves unrestricted access to each other's bodies. Any time Ethan was around Katie, he was free to grope her, feel her up, squeeze her hard nipples and finger her wet pussy, or to do anything else he felt like doing to his sexy, naked sister. In turn, she was allowed to take the same liberties with her brother, which could go all the way to surprise blowjobs and just regular, full-on sex.

These were the rules by which they wanted to carry out their incestuous affair, and what followed as a result had exceeded their wildest expectations. Although they had been some very horny teenagers already -- Ethan jacked off religiously, while Katie had many sexual partners -- it was nothing compared to the way in which this total sexual freedom had affected their libidos.

On the very first day, the siblings had sex so many times that Ethan decided he must get in a better shape, just to make it less physically taxing on his body. Then the next day, he and Katie fucked through all of morning and most of the afternoon, until Mom came home and treated their children to a delicious dinner. Amazingly, they actually fucked *while* eating it, too: with Katie slowly rocking on Ethan's lap, his hard cock firmly lodged inside her dripping wet pussy.

From there on out, the insatiable lovers had sex pretty much all the time, fucking like rabbits in every spot of the house. Their mom had been extremely accommodating of this "experiment," as she called it, and normalized the fact that her kids were now rutting openly like wild animals, often in full view of their mother!

Totally supportive of their sexual self-discovery, she served them food, made their beds, and cleaned every mess they'd make while fucking each other for an entire day. Moreover, she actually expressed interest in the particulars of their lurid activities, not unlike a mom who would want to know if her kids are doing well in school. She always asked if they felt like they were making the most out of this opportunity, to explore their sexuality by letting their desires run completely free.

To Ethan, the answer was obviously a resounding yes! Every now and again, he would still get this feeling that it was all just a wonderful, erotic dream. Ever since Katie gave him a free pass to fuck her whenever he felt the urge, it seemed like all he'd been doing was thrusting his large cock deep into her heavenly tight pussy. With his teenage hormones in complete overdrive, he was always hard and horny for his hot sister.

Just like now, when he saw her stir and slowly open her eyes; Ethan's cock was already throbbing with anticipation.

"Mmm..." Katie purred sleepily, twisting her head as she followed her brother's movements. He was on top her now, his big stick poking at the entrance to her warm tunnel, while he kissed her neck and gently nibbled at her ear. "Ooh, Ethan..."

"And good morning to you, sis," he whispered, rubbing the tip over the moist lips of her pussy.

"You can wake me up like this any time," she said between ragged breaths, her slit quickly lubricating itself in response to Ethan's prodding. "I just love your hard cock, bro!"

"All for you, Katie," he said, bathing his shaft in her leaking juices but carefully avoiding the entrance to her sizzling hot furnace. "Since my slutty sister likes my cock so much, let me just make sure that everything down there is well acquainted with it..."

He continued daubing his rigid meat in his sister's copious moisture, making her give frustrated groans.

"Please," she breathed. "Don't tease me! I'm already so wet... I need you now!"

Taking matters in her own hands (or lips), she lifted her butt and pushed against her brother. Surprising Ethan with her craftiness and agility, she then caught the head of his swollen cock and sheathed it inside the opening to her vagina.

Amused by her eagerness, Ethan let out a breathy chuckle. He braced himself against the bed and pushed the rest of his rock-hard shaft all the way into his wanton sister, making the horny girl squeal in delight as he started rhytmically fucking her again.

***

Linda sat on the couch and felt like she was about to explode.

Normally, she'd be looking forward to the weekend. It was two whole days of respite, away from her stressful, though admittedly rather satisfying job. Especially weekends like this one, when she wasn't on-call, standing by to jump in and douse whatever virtual fire threatened to engulf her company's servers.

Yes, normally a weekend like this would be the perfect time for some cozy rest and relaxation at home. But for the past few days, Linda's home had been anything but normal.

"Yes! Yeees!... Oh my god... Fuck me, Ethan! Fuck your sister with your big cock!... Yes, ooh, yes... oh... Fuuuuuuuuck!..."

She could scarcely believe it. Her teenage kids had been going at it for literal days now, and it was slowly driving Linda insane. No, she didn't have any problem with her children having incestuous sex. What she couldn't stand was the fact that they weren't also fucking *her*!

In a way, she only had herself to blame. She really did everything she could to accommodate their torrid affair. She was acting on a faint hope that by involving herself in their sexual activities, if only from the sidelines, she would make them see her as the hot and horny woman that she was.

Lately, she even stopped being in any way subtle, as her wardrobe at home now consisted of a sports bra and a pair of ass-hugging shorts. Every day over dinner, she would listen to lustful moans that punctuated their eager recollection of the ongoing debauchery they engaged in. And she would drop one suggestion after another: that maybe, just maybe, they could think of even more ways to "explore their sexuality."

And yet, nothing had worked! As far the siblings were concerned, she was simply their very cool mom, strict about grades but super lenient about everything else.

Linda was fed up with it. She decided she was done with being just a mother. By golly, she deserved some of that sweet "sexual exploration" herself!

"Kiiiiiiiids!" she yelled. "Movie night!"

A movie night on Friday was their family tradition, or at least it had been before Katie went off to college. An old-fashioned one, perhaps, but it still worked just fine in the age of internet, flat screen TVs, and streaming apps with huge libraries of content.

Today, however, Linda didn't care much for a movie. What she needed was a pretext, to get her sex-crazed kids to come downstairs and sit with her for a while. Sure, there would be some Netflix involved, but the real point was the chill.

"Uhm... you called us, Mom?"

There they were, still naked as jaybirds. Ethan's cock was sticking out at a right angle, slick with what Linda was sure were the pussy juices of his slutty sister. Katie was with him, of course, holding her brother's hand and eyeing his shaft longingly.

"Yes," Linda replied. "Now that Katie would be home for a while, I figured that we could have our traditional Friday movie nights again. You know, just like the old times." She patted the couch invitingly. "So, why don't you sit down? I've got some snacks ready, and we can pick a film that we'd all like..."

The siblings looked at each other, shrugged, and wordlessly decided this wasn't the worst idea. Ethan went first, sitting maybe two feet away from his mother, followed by Katie who, pretty much reflexively, straddled his brother's lap and began to lower herself onto his pulsing hard-on.

"You may want to face the TV, honey," Linda said with a laugh, causing her daughter to blush and quickly change position. "Alright, I think we are all comfortable enough..."

During the first ten minutes of the movie -- a run-off-the-mill action flick -- Katie and Ethan were actually paying it some attention. Linda seemingly was, too, although she often glanced at the leisurely mating couple.

Over time, however, the pace of action both on and before the screen would rapidly increase. Ethan's sister was now gyrating upon his rigid cock, the sounds of her lusty moans drowning what little dialogue the movie had. The boy was quite worked up as well, cum boiling in his bloated nuts, as he flicked Katie's clit with one hand and groped her ample breasts with the other.

Linda was now openly staring at her kids, who were screwing right next to her, the heat within her pussy growing with each passing second. Previously, she would've simply averted her gaze, trying her best to ignore the primal noises of their incessant fucking. Simply hearing it was hard enough already; watching too closely could make her do things, things she might later regret. But now, having cast her doubts aside, she *wanted* to do those things. Her only regret was having waited so long to do them!

So, she kept staring. And, very slowly, she reached into her shorts and found the hard, throbbing nub of her clit.

"Oooh, brother," Katie started to really vocalize her pleasure now. "You feel so good inside me... I'm getting close... really close..."

Ethan let out a low groan, his hands resting on his sister's hips. He knew he should hold off for a moment now, to allow Katie to reach the bloom of her budding orgasm. With a firm grip he steadied her movements, and his eyes searched for some non-erotic scenery to help him delay his own release. He happened to glance at his mom, a sight that should normally be ideal for this purpose, but his eyeballs almost bulged out when he saw how far from innocent the view was.

"Katie," he whispered, pointing to the side with a flick of his chin. "Look!"

There was no denying it: Mom was masturbating! She had a hand stuffed inside her snug shorts, rapid movement of her fingers easy to see under the tight fabric. Her eyelids were half-shut, breath getting quicker and quicker as she worked herself towards a powerful climax. To reach it, she clearly didn't even need to watch her children anymore, though she was still straining her ears to catch the lewd sounds of their incestuous coupling.

But the noises were gone now. Her kids stopped fucking, and their attention was now all on her.

Linda opened her eyes and immediately met the gaze of her daughter. She was no longer riding Ethan and instead watched her mom with a surprised, curious, and intensely lustful expression. For a moment, they both froze.

But then Katie flashed Mom a huge grin, and soon started grinding against her brother again. Every now and then, she would glance at her mother and smile, locking eyes with her as she groaned at the feeling of Ethan's thick cock stretching her insides delightfully.

Linda's heart was racing: she was finally getting somewhere! Trying not to appear too excited, other than from her arousal, she gingerly went back to stroking her inflamed pussy. Her children were once again mostly focused on themselves and their mutual lust, but both of them would occasionally gaze at their mom and smile.

No words were said. The TV was still on, but no one was paying it any attention. Linda's loud moans, Ethan's grunts, and Katie's cries of pleasure filled the air of the dimly lit living room. The whole family was now building up towards a huge climax, together climbing their way to the peak of their shared ecstasy.

"Sis... I don't think I can hold it much longer..."

"Just... a little... more!... oh... oooh... oooooh!... OOOOOOOOH! OH YES! OH GOD! I'M CUMMING!... I'm cumming, Mom!! I'm cumming so hard on your son's huge cock!"

Katie cried out her release, trembling and squirming as the violent orgasm ripped through her young body. Her arms flailed, looking to grip something that could steady her through the overwhelming experience. Instinctively, Linda reached out with free hand and caught her daughter's arm, holding her firmly as the girl kept spasming and crying out in orgasmic bliss.

"AAARGH!" Ethan let out a savage growl. "I'm coming... too!..."

His sister's wildly quivering pussy was instantly flooded with Ethan's massive load. Just like Katie, he kept coming and coming, blasting her love canal with a great torrent of white hot cum. The rich seed soon leaked from her overflowing vagina, ejected by the forceful convulsions of her ongoing orgasm. It dribbled down Ethan's rampant cock and trailed further, forming a small but growing puddle underneath the shaking couple.

"Oh my, Ethan..." his mom spoke in a quivering voice, "this is so much cum!... You'll stain the couch... Oh god, it's so hot..."

Horny like she hadn't felt in years, Linda fingered herself furiously, her own release so close at hand... Her children were still cumming when their mom finally added her voice to the lewd chorus, moaning throatily at the apex of her long-deserved orgasm. Clad in a skimpy sports bra, her plump breasts shuddered on the waves of carnal joy, and she slid limply, momentarily paralyzed by the sheer intensity of her spine-tingling climax.

Linda's shorts were a complete mess, drenched in copious juices from her gushing pussy. To the side, her insatiable children were sitting in a puddle of her son's cum, panting heavily after cumming right along with their mother. The movie, long forgotten, was still playing on the big screen, the main protagonist now involved in some kind of a car chase.

But it all didn't matter.

What mattered was that Linda and Katie were still holding hands. Mother and daughter have at last come together, revealing to each other the incestuous desires that they both shared. Their son and brother was right there, too, ready to begin with them a new chapter in their voyage of sexual exploration.

"Well!" Mom finally said, relieving the lingering tension with a good laugh. "I'd say this was the best movie night in ages!"

***

Linda opened the door to her bedroom and flicked the light switch on. She turned back and cheerfully invited her slightly nervous children to come in. While they had obvious reasons to hesitate -- Mom's bedroom had always been uncharted territory -- it was clear that what happened between them was about to change things.

A lot.

"You can sit there," Linda pointed to a cushy armchair in the corner. "Ethan should be quite accustomed to having his sister on his lap by now," she added with a smirk.

Emboldened, the still-naked duo took the proffered seat, but Katie didn't impale herself on her brother's cock right away. Instead, she let the erect shaft jut from between her legs, resting against her pussy and lubricating itself with her juices. A cute yelp escaped Katie's lips at the contact with Ethan's hard-on, but the horny siblings were otherwise quiet and still.

"I've been awfully patient with you kids," their mom began, facing them as she sat on the bed. "I accepted that my son and daughter were having a sexual relationship. I've tolerated you having sex not only when I'm at work, but also in the evenings. I agreed to the idea of the two of you going nude, of you fucking all over the house, and even of you doing it right in front of me if you wanted to," she paused for a breath, looking at the increasingly disquieted faces of her children.

"I've been very accommodating, feeding you and cleaning after you, so that you could stop worrying about everything else and focus exclusively on your, ahem, sexual growth and discovery... And you've been doing just that, haven't you? For the past week, you've been going at it practically nonstop! I doubt you've ever gone more than an hour between your, uh, sessions, and it's an hour only because that's how long Ethan usually works out. You really want to spend the entire summer on nothing but sex, huh?"

Though the answer was obvious to them, the siblings weren't so sure, not anymore, that their mother would like to hear it again.

"We... kind of do, Mom," Katie tried it anyway. "When I saw Ethan's cock and realized what a stud he was"--her brother's face lit up with a cheeky grin--"I simply wanted him to be my fuck-buddy. But once we actually started having sex, and we stopped wearing clothes and all that... Well, it just got crazy! It's so naughty and exhilarating, to know that we can just fuck each other at any time. It's like we both know that even if we're done for the moment, it won't be long before one of us wants to go again. So, why even stop?" Katie asked with a disarming smile. "Well, okay, I'm sure we'll eventually calm down somehow, because nothing this good can last forever. But I don't want to think about it... Right now, Ethan and I are simply loving this, and we absolutely want to continue."

Ethan was nodding along vigorously. He wasn't completely sure he agreed with everything his sister told Mom, particularly the part that predicted the eventual end to their activities, but he sure as hell wasn't about to contradict her. For now, Katie was taking his throbbing dick inside her pussy at all hours of the day so, in his view, this made her correct about pretty much everything.

"Huh, okay," Linda said hesitantly, trying to not to show how jealous she was of this passion between her children. "Well, if nothing else, I suppose it's a fun way to spend your summer break. Just make sure you *do* calm down at some point, alright?"

"We'll try," Katie said, looking at her brother who understandably didn't want to commit to anything. "But right now, we are just super horny. Leave us to our own devices, and we will be fucking all day, every day! I guess you know that already..."

"Yes, I've noticed," she said, a soft sigh escaping her lips. "It has been rather difficult to ignore. Sometimes, I would get frustrated enough to think you are doing this on purpose. I'm sorry, I know it's obviously not the case, but I was just --"