Having a bad case of the shits in the night time. PM=nightime BM=bowel movements, therefore PMBM=nightime bowel movement.
Dan-"Hey dude, wanna go out to a club and pick up some babes tonight?"

Jeremy-"Nah dude, I'm feeling a bad case of the PMBM coming on"

by peter Stefanos September 23, 2006
A bowel movement that takes place in between 1:00pm and 12:00pm.
That pm bm destroyed my toilet dude.
by brainpowerintheshower6969 June 20, 2010
noun: a bowel movement occurring during the second half of the day.
Queen of England: Sir, do you take thy daily deuce in the morning, as I do?

Factory Stiff: No, your Highness. Ever since I got on third shift I've been rocking a PMBM.
by honkus mcduck May 14, 2009

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.