Term derived from slang. Normally used in England. I mean you'd sound like a bit of a nob if you used this in America or something.
Anyway, basically it translates to "What's up? You're extremely attractive" It is now mostly used by teenagers who are wannabe gangsters (like I stated earlier) or a group of guys saying it as a joke.
wagwan is a jamaican patois or jamaican english way of saying "whats up"
piff means "high quality", and ting is the autistic version of saying "thing"
a bbm pin is the numbers you'd use to contact someone on the blackberry messenger