Blow an O-ring 

Taking a huge shit to the point that it makes your anus hurts for hours afterward.
A bit of a rip on Challenger's explosion due to a bad O-ring.

"Dude, all that Chinese buffet is going to make me blow my O-ring."

Guy 1 "Why are you walking like that? Did you just Blow an O-Ring? "
Guy 2 "Ate some nasty food the other night...God it hurts!"

Blow an O-ring by HankHill October 2, 2008

blow an o ring

taking such a tremendous shit that it feels like ur asshole just blew out...

oh man, that was one explosive shit, i think i just blew an o ring..

blow an o ring by HoMeS March 11, 2004