Screaming at the Lizard

It relation to the Blumpkin where you are getting a blow job while shitting. However, in the case of Screaming at the Lizard you suddenly feel the urge to piss, voluntary or not, in the mouth of the girl/guy that is blowing you.

Dave: Dude, last night I was getting blumpkin from Judy.
Joe: How'd it go?
Dave: Bad, it turned into a Screaming at the Lizard