A machine gun couple is a interracial couple, especially between a white woman and a black man, but it can be between any races. The use of the word machine gun instead of any gun is partially inspired by Jacob Zuma singing that he will shoot the boer with the machine gun
Yuck. I see a machine gun couple between some black guy and a white woman. Ben, do you have my machine gun? I need to shoot them.
When a car battery doesn't have enough juice to turn over the engine, but has enough to make the starter produce a very loud fast clicking noise, which is very close to the sound made by many sub machine guns.
Will usually scare the living shit out of anyone standing near your car.
Dude 1: That guy had a machine gunstarter. It scared the fuck out off me!