Due to her husband's affair, her mother's best friend, Yuuri, who had quarreled and left the house, decided to stay at home for a while. Satoshi was excited by the sex appeal and sexy body that I couldn't think of as my mother's classmate, and my heart was pounding ... Satoshi, whose curiosity about Yuuri cannot be suppressed, peeks into Yuuri's nakedness while changing clothes in the bathroom. Satoshi who returned to the room involuntarily masturbates with a plump body of Yuuri, but on the contrary, that masturbation is seen by Yuuri.