Barf is one of Nature's ways of explaining to you something your mom always told you but never explained: That not everything that will fit in your mouth belongs in your mouth.
Barf is one of several things — all of which have pert little four-letter Anglo-Saxon names — that Nature tries to get you not to put back in your mouth. Nature does so by giving them unpleasant aromas. You can put any of them in your mouth, if you really want to; you just need to think twice about it.
Barf was originally devised in 1953 by Peter Pan. Yes, the same one who will never grow up. Ironically, the barf scenes were not in the screened movie, but have been restored to the Director's Cut on DVD.
Not unlike Rocky Horror, the deleted scenes spread like a meme to party colleges around the world, spawning a veritable ritual of college life.
It remains a specialty at places such as Michigan Technological University, where it is a workable alternative to freezing to death.