First but not necessarily best of Hammer's sexually explicit vampire trilogy does feature a nude Ingrid Pitt as the lead lesbo vamp Carmilla. Another hot babe, Madeline Smith, who was James Bond's first sexual conquest in the film "Live and Let Die," is Pitt's topless victim.
Peter Cushing also shows up to do some vampire hunting, thankfully leaving his clothes on. Not much else to report here. A landmark film only in the sense that it marked the first time that Hammer went straight after the sex market. There are some nice naked bodies in this movie, but overall the film is a disappointment when one considers it's from Roy Ward Baker, the director of the amazing "Asylum" and "Scars of Dracula." It seemed like the sexual content didn't sit well with him. Other, similarly themed Euro-horror films, like "Vampyres" and "Daughters of Darkness," are definitely better.
Followed by "Lust for a Vampire." Still enjoying a massive cult following, in 1998, Pitt wrote "The Bedside Companion for Vampire Lovers," a book about horror films.