When one has to take a shit, but cannot reach the bathroom at the time and is focusing on not farting or soiling themselfs, this is also known as having "one in the chamber". This usually comes with a slumped back, slow long paces, a serious face, and a humped walk. And usually when one releases one from the chamber they have what is known as, the release face.
WIPE OFF THAT CHAMBER FACE
by Onebulletinyourchamber June 18, 2011
Somebody with a strong and defined face, like a chamber of steel.
Wow, I bet he's in good health, just look at that chamberface
by Ronnie's Shed February 17, 2011