1. shit your pants.
2. doo doo on the floor.
3. dookie on any surface under or near you.
4. clog the shitter something awful!
It can also indicate: mass chaos; a conglomeration of fuckitude; a situation fucked up beyond all recognition, aka FUBAR; a Mongolian Cluster Fuck; when all fucking hell breaks loose.
Pam told everyone at the office she was screwing Tammy's boyfriend. When Tammy found out, there was a shitsplosion of apocalyptic proportion involving Pam stapling Tammy's ear to the floor, then yanking out her navel ring AND her weave!
That thirteen-car pile-up caused a hell of a shitsplosion on I-95 at rush hour yesterday.
My mom found my weed in my panty drawer, so there was a complete and utter shitsplosion at my house last night when she told my dad.