A literary mother tied up her son's friend and made her cum inside her slowly, and she was filled with dirty talk.

Yu graduated from the national literature department and for a while she had been aiming to become a literature researcher. He married a husband he met while he was in school, and now he also has a high school son. He was living a noisy yet peaceful life, but one day, his son brought his friend to hold a study group. As he spends time with his young, strong son's friend, Yu's hidden sadistic personality begins to ache. So Yu plans to not only teach school studies but also sexual matters...