Despite the feeling to say to your friends"sup!" Sup is actually a mixture between a best friend and a friend. If your best friends with someone, but have lots of arguments, but don't want to be 'just' friends, sup is the perfect thing to be!! Sup's are fun, kind, free willed, and don't get angry quickly. They are patient with each other, and despite not knowing the other for a while, can still be a loyal Sup!
"I'm sorry for the argument. I don't think we can be besties."
"I feel friends is to small of a relationship thought"
"Ok. Let's be Sup's instead."
The word you say to great your gangsta buddies. The gang version means lets meet up and bangsomeone. The version you say to someone else means I want to bang you.