Mother-in-law's pain

A new mother, Natsumi, has married into the house of Noboru, a prep school student. She is kind to Noboru, and is also beautiful and has big breasts. Although Noboru is interested in Natsumi, he is too close to his father and cannot even eructate in his behavior. One day, his otaku and perverted friend Kosaku comes to his house. And then the incident began. Natsumi ended up having sex with Kosaku. Is Natsumi's hidden face lustful? ...However, Natsumi's true heart and feelings were elsewhere. it is···.