The period of time, before which you must eliminate solid waste matter from your body, where your sphincter slightly opens to slowly relieve the pressure caused by heavy amounts of poo gases in your rectum. Quite simply, right before you have to take a big dump, shit stink creeps out of your ass in long, silent, slow-like poots. The only remedy, of course, is taking that big aforementioned dump.
Bro 1: Dude, what's goin-...yo man, it smells like shit in here. Did you fart?
Bro 2: Nah guy, I'm venting.