mt. Saint Helen 

When one deffacates into a females mouth thus causing the female to gag from all the shit going down her throat. The shit sliding down the side of the mouth and, mixed with throw up gives it the effect as if though lava is flowing out of an erupted volcano.

When my girlfriend pissed me off I gave her a Mt. Saint Helen. She shut the fuck up real quick!!

mt. Saint Helen by Spasa Jovanovich January 2, 2008

Mt. Saint Helen's Disease 

An eruption from from deep in Your bowels resulting in the bowel, under side of the toilet , A narrow band on the upper part of your calves and anything in a possible 3 foot circumference With an even coating of a clay like foul smelling material. In some worse cases the right or left butt cheek is left dangling by pieces of flesh.

I never should have gotten those gut bombs from the convenience store.
Bad?
Mt. Saint Helen's disease.
Who's cleaning that up
??????

Mt. Saint Helen's Disease by DARTH STEELER July 6, 2014

Mt. Saint Helens 

When one ejaculates in a woman's mouth (not necessarily named "Helen"), then the woman proceeds to do a headstand while holding said cum in her mouth, then she forces a sneeze causing an eruption out the nostrils.

My lady was on the rag so instead of sex she gave me a Mt. Saint Helens which erupted with glory.

Mt. Saint Helens by legalbandit January 4, 2021