HBAD-689 — I'm F** To Serve My Frustrated Big-Breasted, Big-Assed Gal Sister Whenever I Have Free Time. Oto Alice

Ayumu, who entered a high school in Tokyo, doesn't like living in a dormitory, so he lives with his gyaru sister who lives in Tokyo. However, his gyaru sister is constantly bringing various men into her room and having sex with them, so Ayumu, who is a teenager who is curious about sex, is worried about it and can't concentrate on his studies...