An alternative to walking/running around a vehicle, in which a running jump is taken onto the hood of a vehicle (preferably yours), landing body first, and letting yourself slide across the hood to the other side of the vehicle, where you land on your feet.
Easier with a good wax job. Not recomended on full-size vans or Hyundais.

the whale tail is the shape formed when a g-string rides up high over a womans trousers

see bo-duke it...basically means jumping into a car by unconventional means, i.e. over the side of the door or the back (only possible in a jeep, convertible, pick-up truck, or similar vehicle).