What is Xlut?
A chick who goes so far above and beyond the call of normal slutdom that she earns herself an alternative spelling. Primarily it serves as a written description as its pronounciation is so similar to slut, but with IMs, texts and emails, I'm sure this word will be useful.
A girl who goes to multiple parties or bars in a night, and has sex with a different guy in each location is a xlut.
An ex-who bangs your best friend and your worst enemy just to fuck with your head is could be categorized as a xlut.