When a person has to poop really bad and they can no longer buy time by farting
Jimmy let out a string of farts in an attempt to relieve the pressure of his impending poop. He carefully allowed one last fart to slip out. Jimmy then knew that the next thing to exit his ass would not be flatulence. He was out of gas.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"