Jeff couldn't help but glance at his little sister Emily's jeans. She had grown a rather large erection while beating him in their little video game tournament among themselves. Emily certainly noticed this glance and used it as an excuse to turn things up a notch between them.
Emily pivoted on the couch in a quick, forceful move to sit on top of Jeff, facing him. "I won the game and now you need to suck my dick. You've been teasing me this whole game and this erection you were just admiring is your fault. Winners get their dick sucked, that's the rules."
Despite how loose of a fit Emily's jeans appeared to be before the game, Jeff felt like he could feel every inch of her dick (which was larger than his) weighing down on him. Worse, he realized that it felt like he could feel every fold of his little sister's pussy sitting nearly right on top of his own dick. Jeff supposed that her erection was filling her jeans too much and giving her the worst camel toe based on what he was feeling.
"I don't recall agreeing to those rules," Jeff admitted, both kind of scared of his new much more dominant little sister and also turned on by it. He tried to just maintain eye contact and not blink too much in the hopes this game of chicken was just another tease.
Emily chuckled, an evil, dangerous, chuckle, "Last I checked, I have the biggest dick in the house, which means I get to make the rules. What are you going to do about it, big brother?" She leaned forward until her small but growing tits, barely held together in a very revealing crop top, were pushed against Jeff's chest. She used Jeff's chest to further lift her breasts into a bit more noticeable cleavage directly below Jeff's eyes. "My tits are down here, stop looking in my eyes and look at what you really care about, you pervert. If you are good boy, maybe you can play with them after you've sucked my dick."
Jeff couldn't help himself and followed the command to stare down at his little sister's enhanced cleavage. It did not help Jeff find any more words to say.
"Or maybe," Emily continued with a hint of sadism, "you would rather get a punishment than a prize. I could spank you a bit for breaking the rules and then tell mom that you weren't playing nice with me and weren't playing by the rules. I'm her little sweetheart, maybe she would ground you for it."
Jeff gulped.
Emily unzipped her jeans to let her erection free to flop out onto Jeff's belly. "Which do you prefer, prize or punishment?"