Possessed by sex

A bizarre sex-ritual commences. One by one, the witch Isadora Satanus and her female followers sexually abuses a man. But they get interrupted unexpectedly by a wild lynch mob? Cut to present time. A film team is shooting an erotic thriller at the castle, there, according to the legend, the witch was burnt and still haunts the place. The exciting environment makes both the actors and film team horny, and the shooting develops into a regular hard core movie? But something pleasantly evil haunts the castle ? and one by one they start vanishing without a trace?