Coming hard, Tracy slammed her cunt down onto her brother's cock, grinding her exposed ass in a frenzy, gulping and gasping as she came.

"Ooooh, shit!" Tracy screamed, her head thrown back as her ass twisted. "Shit, shit! I'm coming, Bill! Ohhh, fuck, I'm coming!"

Susan watched intently, her gaze blazing on her son's balls, anxious to see if he, too, would come – or even if he could come. If Bill could not squirt yet, she would be very disappointed. As much as Susan loved a hard cock, she wanted one that could erupt in that frothy, boiling spurt of come juice. Only once before Susan had sucked the cock of a teen who could not come. Although she had enjoyed it, as did the teen, it was his lack of ability to come that disappointed her. The taste of thick, creamy come juice was the ultimate for Susan. She liked to fuck a teen, but much preferred to suck him off and let him gush into her mouth.

If her son could not yet come, she would still love to have his hard cock in her mouth or even in her cunt. She knew it would excite her especially because Bill was her son. That alone would make her come, whether he could or not.

So, staring intently at his balls now pressed against his sister's ass his cock no longer in sight, Susan watched with a great deal of interest. She had her finger deep inside her cunt, no longer fucking herself with it.

And then Bill came!

She saw his balls starting to writhe, growing tighter yet. The only sound he made was a long, drawn out sigh, but his hands dug tighter into his sister's creamy ass.

"Ooooh, Bill, Bill!" Tracy squealed. "I feel you! I feel your cock squirting in my cunt! Ohhh, honey, give it to me!"

Tracy rolled her ass about in a tight circle, her cunt drawing at his spurting cock with waving, squeezing motions, sucking the jism from him.