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"
Dan-"Gross"
Jeremy-"Nah dude, I'm feeling a bad case of the PMBM coming on"
Dan-"Gross"
by peter Stefanos September 23, 2006
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.
Factory Stiff: No, your Highness. Ever since I got on third shift I've been rocking a PMBM.
by honkus mcduck May 14, 2009