the act of rollin' coal. When you have a tune on your diesel truck or have turned up the injection pump and you mash the throttle overfueling the engine until the turbo spools up, producing a large cloud of thick black smoke. Its fun to do, but you can't go around doin it all the time as enviromentaists hate us enough already
> Did you see me roll coal all over that group of enviromentalist protesting the diesel truck lot?