The odd and often smelly bowel movements formed from a night of heavy drinking. Most beer shits are water based aqueous fluids. College students are particularly susceptible to this occurance.
Student #1- "Dude, I gotta go home."
Student #2- "Why, man?"
Student #1- "I gotta shit sooo bad."
Student #2- "There's a bathroom right there, just use that one."
Student #1- "No, dude; this isn't just any shit, I drank waaay too much last night I'm about to lay down a beer shit."