Phrase used to describe a large collection of Niggers moving in any direction.
Although often used for comical effect by white people to Express the general feeling that black people cause trouble and should be locked up(1), It was originally used as a heads up for white people that the offending nigs would not understand to avoid being terrorised by large crowds of nigs(2).
1.White Kid(Marvelling at the Coons eating habits) : "Lol Check it out, Jailbreak outside Sam's Chicken."
White Kid 1: "Heads up, Jail Break at 5 o'clock"
Kid 2: "Shit!, i'll throw a Banana in an opposite direction, that should distract them for a few hours"