Do you enjoy sex with ghosts? Apparently many people do, including Ke$ha and actress Natasha Blasick. One medium cautions: "My opinion is to avoid ghost sex in the same way one would avoid sex with any stranger."
From Mancunian Matters:
“The experience described as ‘ghost sex’ may be related to a condition known as sleep paralysis, which renders a person awake and aware – but unable to move with a sensation of something heavy pressing down on them," (Hawaiian medium Patricia Mahi says).