When a younger brother who came to the city to take an exam secretly stays at his older sister's women-only share house, he is easily found by the other residents and is in big trouble! Or so you might think, but the residents, who are horny from the no-male lifestyle, are curious about his younger brother and are in a welcoming mood! However, he can't resist the defenseless panty shots and breast shots of the women who are used to living with only women, and he gets an erection... Of course, he is found, and from that day on, he is made to get an erection with blatant seduction, and is asked to have sex as a dick pet for the frustrated residents!