The unholy act of sneezing so violently that you accidentally poop a little. Often the result of a trapped sneeze that builds pressure like a shaken soda can — and your butt ends up being the weak point.
"I tried to hold in the sneeze, but when it finallyexploded, I sneezesharted so hard I had to change pants."
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.