She Did What He Wanted(1971)

Eddie, a sexually frustrated young man, buys a book on hypnosis and learns the art of mesmerism. He uses his newfound talent to hypnotize Nora, a lovely young housemaid, ostensibly to help cure her headache, but then he transforms her into his loving sex slave. Emboldened by his first acquisition, Eddie then proceeds to start building a stable of female slaves.