No, she doesn't have the strength!

Despite her best efforts, Shiro's inexperienced asshole is too tight to allow anything this big past its sphincter with her measly pushes.

"You're going to have to do it." Shiro says.

It takes James and his two slavegirls a moment to understand that she is talking to her step-brother.

"Are you sure it's not going to, you know, damage you?" Sora asks cautiously.

"The diamater of a billiard ball is 5.25 inches." Shiro speaks out loud. "Based on my calculations, my anal sphincter is able to stretch to 5.4 inches before there is a risk of any notable long term harm, and the risk remains trivial until nearly 6 inches."

Sora smirks. "Of course you've done the math." In truth, this is a bit performative. He has full confidence in his sister, and knows that she will have taken all possible factors into account before agreeing to this challenge.

Sora steps up behind his sister and takes the ball. Spreading one cheek open with his left hand, he uses his right hand to **** the billiard ball against her sphincter.

He has to push really, really hard, but with a sudden quiet pop, the ball slides in and promptly disappears.

Shiro squeals with distress at the overwhelming and more than a little painful situation, but she has avoided elimination for now.