This word, with many different spellings, is a substitute for "Hello, what are you doin?" used mainly by the youth of England (mainly private school kids, and "gansta's" in state school education) to sound like hard, old Jamaican drug dealers. Meaning: "What is going on?" (i.e. a replacement for sup (what is up?))
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