Based on the erotic game by POISON. 
 
The tutors of the main character, Masato, are "the sexually vicious sisters" he had known since childhood! Haruna Shinjo, the celebrity older sister, combines brains, a fine pair of eyebrows, and the worst kind of personality. Serina Shinjo, a college student with a selfish personality and body, is full of gaps. He is constantly mistreated by both of them, and is already fed up with his life. Then one day, Masato meets Sakiko Ichinose, the owner of the secret club "Gentildonna" and is handed a hypnosis device. Using the device, he is told that he can manipulate any person's mind and body at will. 
 
(Source: Mediabank, translated)

Based on the erotic game by POISON. 
 
He has been treated like a servant by his older childhood friends, sisters Hina and Serina, but worst of all, Hina ends up tutoring him for his entrance exam. One day, however, the owner of a secret club comes in and gives him a hypnotic product. He immediately uses it on Serina, his sister's servant, to "make her understand" his intentions, and begins his lewd revenge by cuckolding her and enslaving both sisters as sex slaves!! 
 
(Source: Parabook, translated)

Masato Shimamura