What is Poopsie Pants?
1.
(n.) one who has done a massive wet crap in their pants. Most of the time, the poop can be seen seeping through the underware, etc, and usually there is a horrendous odor associated with him/her.
"Yo! Did u see that Poopsie pants over there?!?!? He was leaving a streak of messy poo when he walked past!"