Billy goes to bed.

Billy lay on the floor for a moment, still dazed. After a few minutes of contemplating his situation--he was still reeling at the fact that Anna had dominated him so thoroughly--he gingerly got to his feet and headed to bed.

It was late, so Billy tried to get straight to sleep. But it wasn't long before he started tossing and turning. He hadn't taken a shower before bed, and he could still smell Anna on him. And his dick hurt like hell, and he knew it wouldn't stop until he'd rubbed one out.

He didn't want to think about Anna while he was doing it, but he couldn't help it. Images flashed through his mind from the last couple days. His initial ill-advised idea to have Heather knock him out. Her transformation from sweet, caring mom to bold, sassy domme. What had he been thinking, giving her those loaded gloves?

And then Anna, following in their mother's footsteps. Knocking him out with the loaded gloves. Pinning him down and extracting the truth from him. Challenging him to a fair match...and beating him badly. Her celebrating over his woozy body. Indisputable physical domination. Her straddling him, stroking his cock, denying him the orgasm he desperately needed. Indisputable sexual domination. Had she known how to do that before? Or did she learn it on the fly, like she did with boxing, or the many other things she could do better than him?

Billy's cock was as hard as he could remember it being, and he started jerking it furiously to the next few images that crossed his mind. Anna undressing, straddling him again. Her naked butt sitting on his face, grinding and rubbing against him, humiliating beyond what he'd previously imagined. And after all that, her careless slap to his face that knocked him ****. How far he'd fallen, from being a champion boxer to a glass-jawed joke, getting knocked out by a single contemptuous, playful slap from his little sister.

Finally, his cock could take no more. "Annnnn--nuh!" he gasped out his sister's name involuntarily, powerless to do anything but hope she couldn't hear him from her room. He started shooting cum all over himself, not making any effort to stay clean but solely focused on the overwhelming feeling of pleasure and release.

Afterwards, as he caught his breath, the sexiness of his situation faded, and only the humiliation remained. His reputation as a boxer was in tatters, his mom and sister had both dominated him, and now his sister was taking it up a notch by making him her sex ****. Whether she was doing it knowingly or unknowingly wasn't clear to Billy. What was clear was that his refusal to kiss Anna's ass would be the last time he defied her...at this moment, he no longer had the willpower to resist.

What would Anna do to him next? he wondered. Would she tell people how she could beat him up? Or would she keep it their little secret? Would she branch out into other forms of domination? Or would she stick to beating him up, knocking him out, and letting him snooze at her feet?