To hit someone with a seamen filled condom across the cheek.
Joe: dude, me and my girlfriendhad sex lastnight.
Marty: Awesome! wut was it like
Joe: i rubberwhacked her cuz sheswas being a bitch
Marty: why,wut'd she do?
Joe: she had her period, and made fun of my huge cock because it was so huge and cockish
Marty: Yes. Yes. Y-E-S.