Irritable Bowel Syndrome. It's when your sphincter releases liquid hot magma loaf-demons unreservedly and without reason.
Cordova: Hey Jim, what's the deal? Why is there brown fluid spilling down your legs?
Jim: It's IBS. And it burns.
Cordova: Haha, it must suck to feel like a moron.
Jim: stfu bbq!
Cordova: Roflmao knewb, I'm not the one with IBS!