Sex Ritual of the Occult (1970)

A "fake-umentary" adult movie. Vincent Stevens ("Narrator") plays some kind of scientist, who introduces the scenes supposedly depicting real witchcraft rituals. They do not. He does reveal that the parts are played by professional actors. All the scenes are made on the same set, with an alter of some sort, and at one point a coffin. In each scene the players continue to wear the same Satanic costumes, which are soon shed.