Biffida is a term used to describe the smell of shite. Biffida is not simply shite on its own- instead it is a mixture of sweat, shite and an extreme lack of soap. This builds up to creat a terrible smell.
Prevailance of Biffida did not come to light until February 2011 when a group of English Students visited East Asia. Within several weeks it became clear that all of their clothes began to stink of Biffida.
As of July 2011 the issue of Biffida has not been resolved.
Dude, why don't you wear your blue shirt? It's got Biffida. Oh, what about the green one? Biffida too.