The defintition of the word litterally means "I Don't Believe it!" or "Holy Crap!" It's simply an exclaimation used to suggest shock. The Phrase comes from the Movie "Live From Baghdad." Thats the only place I've ever heard it used.
This phrase can be taken literally and is often hilarious if people look at you strangely for saying it.
Guy 1: Dude! the internet is up again!
Guy 2: Well Fuck me with a Hot Poker!
Guy 1: Heh... no.