Oyako Mix Ijiri ~Mucchiri Haha to Binyuu na Musume no Inniku Kaihatsu

The protagonist is a cram school instructor famous for helping his students get excellent results. One day, he is contacted by his former high school teacher, Miyako, who is looking for someone to tutor her daughter, Kasumi. Since he always had a huge crush on Miyako, he decides to accept her request, whilst keeping his inner feelings hidden. The mother and daughter pair are thrilled that the talented tutor will regularly be coming, but they have secrets of their own. Lately, Miyako has been sexually frustrated, and Kasumi, who has no experience, has been hiding a growing interest in sex. What kind of pleasure awaits in their future? [Translated from DLSite]