The result of trying too forcefully to release a fart: a spatter of shit in your pants. Also referred to as a GK. The term is derived from a story read to Calvin by his dad in Calvin and Hobbes.
"Wow Robbie, in trying to impress us with a nice loud fart, you shat in your pants! Gooey kablooie!"
"Last Saturday I tried to fart but GKed instead."