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.
