1) To drive your car slowing, so you are able to jump out and dance next to it, or climb onto the hood of the car, and dance on top of it. The phrase Ghostriding originated by the "Hyphy" scene in the Bay Area, California
2) To ride a motorcycle/ bike and jump off the back of it, while it is still going. Therefore it looks like there is a ghost driving it down the road.
1) "I wish I didn't crash going ghostriding nightly."
"Oh, Brother that ain't hyphy."
2) "Did you check out that sweet ghostride? The bike drove for at least a mile on it's own.