First usage among gaming communities in the late 1990s; probably derived from running after an opponent while facing their rear (ass). Used in game types such as Capture the Flag in which, once two players have passed one other, they should go for the flag. A player who turns round and follows an opponent is only hunting for frags, hence arserunning is frowned upon.
- (US, video games) To follow and shoot at (somebody in a first-person shooter game) after having passed them.
- One of your players assran me at every opportunity.
- You were assrunning for the whole game.