For several years, office lady Kumi has been forced to drink the semen of middle-aged men as a sex slave. Due to intense livestock-style masochistic training, her body has become so dependent that her fingers tremble if she doesn't consume semen at least once a day. A true female masochist who transforms pain into pleasure—this is a documentary of her complete domination. Part 4 includes anal hooking, beating, pubic hair burning, and the humiliating bed train, escalating her experiences to even deeper levels.