Yes (scissors)

"No, I don't think so." You smirk and throw out scissors... And look up with dread in your eyes as she throws out rock, now smirking back at you.

"Sit down and spread em." Your sister says and you reluctantly listen, watching as she jumps and folds her legs, feet touching her back, kneecaps down.

She comes down on your left ball squarely and you both hear it squelch and pop. She rolls off, grinning as you writhe. "Ready for the last round?"