An act of aggression that occurs "when fools need a beating, and you call your homies, and put in some work."
If you don't get yo' hands off my bitch, I'm callin' for black-up.
the traffic caused by a group of African Americans blocking the hall and preventing Caucasian students from moving to their next class.
Tom: Dude, why arent we moving?????
Andrew: Man this is the Math hall. This is probably the black-up from all those black guys who walk slowly.