when one group of males on a beach or dock throw rocks at another less-liked member of the group, often times in a canoe or some other floatable 60-100 feet offshore. The object of the game is to either hit the target with rocks or get them wet by splashing them if you're a crappy shot. This game is best played while intoxicated.
Jim: Why are you throwing rocks at poor Ted out in the canoe?
Tommy: I'ts dock rock! Grap a rock and join in!