My name is Atsushi. For the first time since they started dating, he learns that Mukai and her sister are living together at her house. By the way, my girlfriend is homely and ladylike. Serious and reluctant to have sex. However, her sister's wish is that she is not good at cooking or doing housework, but is active in erotica. She is truly a carnivorous girl. She has a habit of licking and instinctively licks various things, so she wants to be at close range.