A vampire movie

The movie you had been viewing featured a hot male vampire dwelling beneath a girls' school. Each night the vampire would summon one of the many senior girls to his coffin downstairs for not only blood-drinking but for erotic passions. Due to his influence the girls slept in either skimpy bra and panty sets, nighties, or things equally sexy. A friend of one of the girls was investigating the history of the building when you fell asleep...