Definitions by Rabadina

Surprise Bowel Movement 

aka SBM, when you think you are just going to the bathroom to take a piss, and you unexpectedly have the urge to poop.

"Dude, what took you so long to piss? Did you fall in?!"

"Nah man, I had a Surprise Bowel Movement."

Surprise Bowel Movement by Rabadina March 25, 2009