A solid piece of poop blocking the butthole passage allowing prolonged control over otherwise explosive diarrhea.
by Plumpy4000 January 08, 2009
When you're taking a shit, and the initial shit is a regular solid one, but everything that follows after is pure diarrhea.
Joe: I thought I was gonna have a nice shit at first but then I ended up obliterating the toilet bowl.
Gabe: Yeah, that's what you call the poop cap.
Gabe: Yeah, that's what you call the poop cap.
by Andy Stafford November 07, 2015