WARNING: This story contains straight sex, gay sex (oral), bi sex and family sex. All over 18 and all consensual.
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While Marie was experiencing new and amazing things with her brothers and their cousins, their moms were out at lunch. Or rather, that was what they'd told the kids before they left.
Carla had always thought her parents were a bit silly for giving her and her sister names that both began with the "K" sound, even if they were spelled with different letters. But then Katie had gone and married a man named Ken and they'd named all three of their kids with K names and it made Carla feel a little less silly. Kendra, Kyle, and Kevin were great kids, but seriously? All K names?
Carla had been looking forward to this visit from Katie and her family for quite a while now. She only got to see her sister two or three times per year and she missed her terribly in the long months between trips across the country. But this visit in particular was going to be different. Carla was finally going to share the side of herself that she and Katie had ignored since that summer right after Carla graduated high school, before both of them went to college, Carla in Massachusetts and Katie in California. Katie was two years older than Carla, and they'd been as close as twins growing up, and best friends even in their testy and moody teen years in high school. It had been after Carla's graduation that she and Katie had discovered their secret thrill on those lazy summer afternoons with their parents out of the house. The memories had always made Carla's spine tingle, but once they'd moved across the country from each other, they never spent a summer together in their parents' house again. And as desperately as Carla wanted to share those secrets with her older sister again, she had never been able to bring herself to vocalize those desires.
But things were different now. And she was going to show Katie an afternoon they'd both remember.
Katie's feeling on the subject were, ironically, nearly identical to her younger sister's. But she'd started dating Ken right after returning to school for her junior year, and fallen truly and hopelessly in love with him. She'd been unable to approach her sister in the way she remembered from that summer ever since. It felt like it would be wrong and unfair to Ken. But like her little sister, things for Katie were different. She suspected Carla had more in mind than simply lunch, but she was patiently waiting for the reveal.
The morning crowds had moved on from the fitness center to the other retail delights of an early summer weekend. Carla was able to park much closer to the doors than she would on a normal weekday morning when the gym was full of early-risers like her getting in a workout before work.
"The gym," Katie whined. "Are you serious? I'm on vacation!"
"It's going to be fun!" Carla said. "I promise!"
"I don't even have gym clothes!"
"Lucky for you," Carla said, "We're basically the same size. I brought extra."
Carla reached into the back seat for a small gym bag and winked at her sister before climbing out of the car. At the front desk, Carla nearly shivered with anticipation when she saw John and his shoulders and pecks and smile, in that order. He was well over six feet tall, with dark skin and shaved head. He was an excellent trainer, at least in Carla's limited experience, but she wasn't here for the usual weekday ass-whuppin.
"Carla!" John said, beaming, His broad smile complimented his his hulking muscles beautifully. "Always so punctual."
"Hi, John," Carla said.
"This must be Katie," John said. "So nice to meet you, I'm John. Carla said you two looked a lot alike, but damn."
Katie blushed and shook the gorgeous black man's hand. If he had something to do with Carla's devious plan, she was definitely in.
"I'm stuck on the desk for a few more minutes," John said. "But you two go get changed and do some warm-up and I'll come get you when Beth gets here to take over."
Katie didn't realize she was staring at John until she felt Carla tug her arm. "Locker room's this way, Kate," Carla said. Katie hated being called Kate, and Carla was the only person who could get away with it.
Carla led her sister to an empty women's locker room, after passing through a nearly empty gym. It was the first time the sisters would be in any state of undress together apart from bathing suits for decades, and Carla was buzzing with anticipation. She took off her shirt and shorts in quick succession and enjoyed the way that Katie watched her. Carla stood in her underwear and waited for Katie to start taking her clothes off too. The bag with their gym clothes sat unopened on a bench near the first row of lockers. Carla liked the way she looked in her underwear, especially now that she was on a regular work-out schedule. Her husband was really enjoying it too, although just like when they were young, Mike rarely had the patience to let her keep her bra and panties on once she'd stripped down that far.
Katie smiled and started to undress. She and her younger sister really were built from the same blueprints, a body type that both of them had passed on to their daughters. Big boobs, big butt, thick thighs. Katie didn't work out quite as consistently as Carla and carried just a little more fat, but then again Katie didn't have a John back home to whip her into shape. She'd have to work on that.
They hadn't been naked together since that summer. Katie felt a jolt of pleasure when Carla unfastened her bra and the weight of her big tits dropped in their cups. Katie took her own bra off and enjoyed the way Carla's eyes followed the gentle swaying of her own big boobs. She remembered the way Carla's tits had felt pressed into hers all those years ago, and the way they had tasted.
There was no denying it now. Carla was extremely horny. Age had only made Katie's body sexier. In bed last night, Carla had finally told Mike about that summer with her sister. The story had made Mike's huge cock so hard she was afraid it was going to rupture. He'd fucked her even better than usual while her sister and brother-in-law slept in the next room and their daughters snoozed in Marie's room down the hall.
Katie hadn't been sleeping when Carla and Mike were fucking though. She'd been trying to muffle her cries of pleasure while Ken fucked her slowly but oh so deeply from behind.
Katie's love for huge cocks predated her relationship with Ken by a number of years, but Carla's had begun her freshman year of college after that incredible summer with Katie. Carla had never told Mike that there's no way they would have dated long term, let alone gotten married, if he hadn't measured up to her very particular requirements in the cock department. And over the last year, to her delight, she had discovered that Mike's monstrous member had been passed down to their sons. Darren more so than the twins. Darren's cock was the same size as Mike's and it made Carla cum just as hard as her husband's. Carla had been fucking Darren for a little over a year, and a few months later she'd taken on the twins. Now on nights that Marie was out of the house with a friend or away for a softball game, Carla had her choice of four huge hard cocks, any of which could stay hard for her and cum for her as much as she could possibly want. She'd even managed to get all three sons and her husband to gang up on her a number of times. She felt the heat and moisture between her legs increasing as she remembered, not knowing that at that exact moment her youngest, her eighteen-year-old daughter Marie, had just been caught naked in the laundry room by her equally naked sons and nephews. Nor did Carla know that her sister Katie was also thinking of the several occasions in the last two years that she'd been fucked by Ken and both of her sons, Kevin and Kyle, at the same time.
Neither sister knew that they'd inherited their love for huge cocks from their mother, or that their father had never quite measured up, and that their mother satisfied her cravings outside of the marriage.
But in Carla's and Katie's cases, their activities outside their marriages were encouraged and ravenously enjoyed by both of their husbands. Both Mike and Ken had full permission from Carla and Katie respectively to enjoy their own extra-marital activities, as long as they shared the encounters in full titilating detail with their wives.
But neither sister knew any of this about the other. They were about to find out.
They were naked now, and neither of them seemed to be in much of a hurry to open the gym bag and find something to wear. Both of them wanted badly to take the other in her arms and explore her body.
"Follow me," Carla said.
She led Katie past the benches and lockers and shower stalls to a door that said Staff Only and punched a six digit code into the door lock mechanism. The lock beeped and Katie heard the sound of a deadbolt sliding just before Carla pulled the door open. A sensor turned on the light for them in the room beyond as they stepped inside. With the door closed behind them, Katie took in the new room.
This one was about half of the size of the women's locker room. On the right-hand wall, the wall that separated them from the gym, was a row of ten or so more lockers. There was a single bench in front of the locker row, and on the opposite wall two shower heads pointed down at the tiled floor with two drains and an apparent slope to direct the running water. There were no dividers, no curtains, but plenty of light. Recessed lighting throughout the smaller room lit it up brighter than the locker room behind them. The last thing Katie noticed before her sister kissed her was the door in the wall at the far end.
Carla couldn't wait any longer than it took Katie to take in their surroundings. She pulled her big sister into her embrace and kissed her hard on the lips. Their bodies pressed together and Katie's lips parted to make way for Carla's tongue. Katie moaned into Carla's mouth and slipped her arms around her body and pulled her even closer. Their tits pressed together, and Carla's bare thigh slipped between Katie's legs and she knew that Carla could feel the wetness of her pussy.
