1). A burnoff happens when someone revs up a car motor while applying the brake, the engine at high revolutions per minute, and releasing the brake. The result is both wheels violently turn and often smoke as the heat from the tires
literally burns the rubber off the tires. As the car travels
down the road there is a tell tale set of blackish tire marks on the roadway in its wake.
2). A burnoff is found in someone's
underwear and resembles the burning tire marks found on streets after races.