backjump = fast sprayed graffiti. mostly made in the time a train/bus is waiting at a station.
"Yo, it was me and Suer, right. On a tuesday night
Had green, brown, black, two blue shades and white
Cosm.i.c stayed home but BIF crew stay tight
Staking out the steel dragon for a true spray fight
In other words a backjump" - Looptroop : ambush in the night
To assert oneself in a particularly obnoxious way without warning or permission. Originally from a Canadian "mockumentary" on the extreme sport of backjumping, in which helmeted participants score points by leaping on the backs of unsuspecting pedestrians, scoring points based on the length of the "ride" and the poise displayed in avoiding arrest or assault by the "back". Seems to have passed into more common use when reports surfaced of viewers of the mockumentary actually performing these stunts.
Don't be backjumping my customers, dude, you're pissing them right out the door!