Committing suicide in a sewer.

when you're hungover as shit after a spending a night drunk as a skunk

Releasing a fart so pungent that it usually causes physical harm to those unlucky enough to inhale. So named because it reeks like a sewer.

when you kill yourself by jumping headfirst into a sewer and drowning in literal shit

When someone is found slumped over dead on the toilet hovering above their own bowel movement having been overcome by methane due to the lack of a courtesy flush, they have committed Sewercide.