The Night of the Living Bed.

Sid and his partner, Norman, on their way to a business meeting, stop off at a cemetery to pay their respects to Sid's dead wife, who they then see up and walking about, and having sex with two ghoulish looking men. The not-so-dearly departed wife has become a member of the Walking Horny, who spread their infection by giving one another hickeys, and are now massing in the cemetery. Barracading themselves in the gravedigger's shack, Side and Norman encounter others like themselves, men and women on the run from the sexually hungry predators encircling the small house.