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 w:Capture the Flag|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 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.