Adult PC Game: Gokinjo Ura Circle - Seikyouiku wa Mama ni Omakase! by Erotica Peach Archive

Our Keko is an ordinary housewife living with her son and husband, and her husband is busy very often. But their son has matured and one day she finds him with her friend Ogura Kasumi having sex. This really turns Kyoko on and decides to start sex education for the guys in the area.