Its some thing you do to one of your friends as a joke and beleive me this shit is funny / you walk up behind them when they are not paying attention and you grab there balls from behind and pull them on to their face because they cant put there hands up to catch themselves so they fall on there face.
John(sneeking up behind josh...)
John: towtrucks josh
josh: oh fuck man that shit isn't cool i couldnt catch myself from falling.
josh (fuck now my face and my balls hurt!)