A dent or scratch (obviously self-inflicted by way of an unseen post, parking meter, parked car, barrier....etc.) Usually seen on the rear quarter panel of a pick-up truck and/or car. Driver is likely unaware of his whiskey stain until next morning/afternoon.
"Hey, check out the whiskey stain on the side of Joe's truck"
by JudgeETOX June 03, 2009