hacking the sack - a game where you shoot your nut from your tip into your bell

a game where you shoot your nut from your tip into your belly button, and if you make it in, you hear a *cha-ching* like a cash register.

I hacked the sack and heard *cha-ching* like a cash register.

My brother hacked the sack and got a *cha-ching* from his belly button.

My friend hacked the sack and his belly button rang like a bell.