It is a painfull term when you are called that from the girl you like. It is the term she uses on you to keep you around while she drools over someone else. This is not just being a friend. It is like being a close friend to a girl, but never being able to advance to boy friend. She hugs every other guy except you, even guys she has never met before. It is a term that means you are good, but not good enough, yet she still wants you around.
Yet it is painfull, it can mean your not enough of a manwhore. Depending on the girl and who you are, you may create a close relationship.