it looks a lot easier to do on a truck (not that im calling it easy) there was this video i saw of two whiteboys that did it, they got out of their honda civic and started like skating along the end of the car, and then got back in it. it was fat
i think it would be easier on a truck because you know how some trucks/SUVs have that step right outside the door, that strip against the bottom of the door.
anyways ghostriding the whip = as has been proven in the post, is basically when you get out of your car while its still moving and skate/run/walk/dance as its moving and then get back in.