Peeing myself
For a certain cause such as laughing, fear, or waiting to long you pee without warning into your pants making a visible stain where your pee was running depending on what your wearing.
i had a friend over, he was playing a one-player game. i stood behind him, and i just started peeing. "oh my god, i just peed my pants" i said. my friend didn't belive me so i showed my jeans. i like peeing myself
pee myself
when you're so overwhelmed with joy or laughter that you could quite easily pee your pants. not to be confused with literally peeing yourself. it's a hypothetical situation that almost never happens.
liv: hey did you see that the new harry potter comes out july 15th?
sara: i know, i could totally pee myself!
sara: i know, i could totally pee myself!