Doing doggy to your girlfriend/lover infront of a window, getting another guy to take over and going outside/inside to stand infront of the window the girl is looking out of.
Ghost fucking is cruder name for ghosting.

having sex with a black person, in a dimly lit room... so it appears as if no one else is in the room...

You have your best friend in the closet, then you start to fuck your girlfriend, halfway through you switch with your friend then sneak outside and start waving at your girlfriend.

Meeting a random person, having sex with them, and leaving before ever exchanging names or numbers; as if you where never there.

Pretending to be interested in a person and pursuing a relationship. Once you fuck him/her, you slowly disappear from communication. Ghost. Each day a few less texts until none at all.

Do your girl doggystyle and when she's not paying attention, switch out with your homie. Then proceed to walk around the bed, acting like nothing is going on. When she realizes its not you doing her, your friend has to quickly pull out and hide under the bed, leaving the impression she was being fucked by a ghost.

Ghost fucking. It's where a tweeker uses a cloaking device and fucks you with out you even knowing.