A game guys play were they go around punching each other in the penis. Girls can also threaten to do so to a boy.
Girl: If you don't leave me alone i'm going to sucker punch you so hard!
Boy 1: Dude me and Eric are having a sucker punch war and he hits wicked hard!
Boy 2: Oh! Man i wanna join!!
*Boy 2 sucker punches Boy 1 thus being added to the game*