Sittin on Steam

A phrase used to describe the unpleasant experience of sitting, prefferably in a place such as class, work, Church, or any other place in which stepping out for a moment is tricky and/or discouraged, all whilst fighting against the powerful and evil forces of an excessively-gasseous bowel movement. This may or may not be accompanied by some "prairie-dogging" or "turtling"; however it is best exacerbated by the presence of a wedgie. Sitting on steam may also be related to a phenomenon known as the "beer-shits", which is characterised by considerable bloating and/or the constant urge for defecation following a night in which an excessive number of beers have been imbibed; although such a relation is not necessarily a prerequisite.

Exe. During the intense closing moments of a football game:
Person A: Yo, who's farting over there? It smells like death.
Person B: My bad, dude. I'm sittin on steam right now, but there's no way I'm gettin up to take a crap now. It's way too close. If I get up, I'll miss the whole thing.
Person A: Understandable.