The living room of their shared apartment was filled with the comfortable hum of conversation as Ava and Max lounged on the couch. The siblings, both in their early twenties, were engaged in a discussion about their love lives.
"I just don't get it," Max said, shaking his head. "None of my ex-girlfriends have ever had full-on sex with me."
Ava raised an eyebrow at her brother. "Well, have you considered that it might have something to do with your size?"
Max scoffed. "What's that supposed to mean?"
"Come on, Max," Ava said, grinning. "You're not exactly packing heat down there."
Max rolled his eyes. "Fine, if you're so convinced that I'm small, why don't you test out your theory?"
Ava's grin widened. "Oh, I'm more than willing to. But I have a feeling I'm going to be disappointed."
Max stood up from the couch, stripping off his shirt, pants, and boxers in one swift motion. Ava's eyes widened as she took in the sight of her brother's impressive size.
"Wow," she said, trying to keep the shock out of her voice. "I guess I was wrong about that."
Max smirked. "So, are you going to back out of our little bet?"
Ava stood up, surprising even herself as she stripped off her shirt, pants, panties, and bra. She jokingly told Max to sit down.
Max's eyes widened as Ava straddled him in the missionary position, guiding his size into her. She gasped at the depth, causing Max to grab her hips and start thrusting.
Ava grabbed Max's shoulders, asking if he was actually having sex with her. Max jokingly replied that he was, causing Ava to jokingly scold him not to cum inside her.
Max's thrusting speeds up, causing Ava to jokingly tell him to stop. Max jokingly replied that he was going to cum inside her, surprising Ava.
Max started cumming inside Ava, causing her to feel him still hard inside her. Max rolled them over, with him now on top, thrusting deeper and faster into Ava.
Ava wrapped her legs around Max's waist and jokingly told him that she was locking him in and that he wouldn't cum inside her again. Max started thrusting even faster, causing his balls to slap Ava's ass with every thrust.
Ava jokingly asked if his ex-girlfriends were afraid of his endurance in bed. Max jokingly asked if he was going to impregnate his own sister, causing Ava to jokingly reply that he might the next time they had sex.
The siblings continued their banter as they reached their climax, the erotic atmosphere of the room filled with the sounds of their panting and sweating. As they lay in each other's arms, Ava couldn't help but feel a newfound appreciation for her brother's size - and a newfound desire for more bets in the future.
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