Beiß mich, Liebling (1970)

One day, while on the job, the mail carrier Engelmann breaks both his legs and is therefore out of action for a long time. His young colleague Peter Busch is asked to fill in for him and take over his route. Busch is not only younger but also considerably more attractive than his injured colleague, so the women eagerly invite him in—women who, from then on, look forward to the mail every morning for hormonal reasons too—and enjoy his company in the bedroom. These “grass widows” are always thoroughly gratified anew, because, by virtue of an archiepiscopal decree, all the male members of the Busch family possess perfect and enduring virility in matters of love—but only if each Busch, as required by the decree, keeps a vow to take up the mail carrier’s profession. Peter also gladly sleeps with the pretty Sabrina von der Wies, much to the displeasure of her uncle Hartlieb. He works as a sex therapist and marriage counselor, and Peter’s potency threatens to cost him his female clientele: where there are no sexually frustrated women, there are no more clients to lie on the couch and pour out their troubles to him, Hartlieb von der Wies. So the exasperated therapist comes up with one dark scheme after another to send the self-proclaimed top stud to the hereafter as quickly as possible. Instead, the sinister Hartlieb himself dies after drinking from a decanter containing poison he had put in it, but shortly afterward returns to the world of the living as an undead creature. He has become a vampire and begins biting necks, while Peter, the women’s delight, takes over Hartlieb’s practice and, as an aside, marries Sabrina. Sabrina then confesses to her new husband a closely guarded family secret: the von der Wies family tree has always had the occasional vampire in it. The two then join forces with an eccentric priest, eventually tracking down Uncle Hartlieb in his coffin and staking him, so that he can no longer interfere with Peter and Sabrina’s love life—or with the living in the area. But the night before, the resurrected uncle himself bit Peter on the neck, turning him into a bloodsucker, as the film’s final scene shows.