a game guys play in which they walk around with half-filled water bottles which they use to hit other players in their junk when they are not paying attention. They must yell "COCK WHACK!" for it to count.
As I stood there staring at a nice pair of tits, my moment of peace was interrupted by an immense pain coming from my groin as a water bottle smacked into it. As I collapsed to the ground holding my agonizing manhood, I heard Nick yell, "COCK WHACK!".
by chester b. arthur February 1, 2011