In the game of beer pong when you shoot and it seems like its going in but it bounces off the rim of the cup, making you miss. By not making it you are being blue balled while simultaneously giving the cup a rim job (not to be confused with butt hole licking).
Blue ball + Rim job = Blim Job
Person 1: Aw man i just rim jobbed that cup! I should of made that!
Person 2:Dude thats the second time this game that you've been Blim Jobbed