Dove gets a double

Dove looks a bit surprised that Shiro was able to make the ball fit, but shrugs. She wastes no time in preparing her next shot. Another beautifully placed cue strike sends not one, but two balls whizzing into pockets.

Shiro looks unperturbed, and retrieves the balls, handing them to her step-brother.

"Do it." Shiro says, with a slightly shaky voice.

Sora shoots her a pitying look, so Shiro tries to reassure him. "Three is fine. The total volume of them all will be 12 pi R cubed, which is approximately 227.29914 cubic inches, to eight significant figures. The average anal capacity of a woman 5 feet 2 inches tall such as myself is-"

"Okay, okay, I get it." Sora can't help but smile as he interrupts Shiro's mathematical tirade. "Just hold still."

Sora gets the first ball almost to the point of no return, eliciting some pained whines from his step-sister. At this point he releases it, allowing it to keep her stretched open, and slowly ease its way back out. But then it is blocked, stopped and pushed back in by the next ball. In this way, with the second ball pushing against the first, Sora pushes both balls into Shiro's asshole in the same swift motion, sparing her from having to go through the entire ordeal twice.

In an instant, the third ball disappears. Now all three balls are hidden snug inside her asshole, leaving her feeling incredibly, uncomfortably full.