Thizzapher said:
if you try it just dont put a brick on your peddal like some other people that tried it
because that will; fuck up your car.
to answer your question, if you havent figured it out, its when you get out of your vehicle, while its still goin. since its goin with no driver, or an invisible driver(like a ghost), its called ghostriding.
never tried it with a car before tho..