Koibito Inai Reki = Nenrei no Onna Kyoushi ga Kodomo Atsukai shite kita Toshi no Hanareta Osananajimi no Seito wo Ishiki shite shimau Hanashi

Otome-san is a high school teacher who's never had a boyfriend in her life. Until her younger childhood friend Hiro became a student in her class, and she suddenly had feelings for him as a member of the opposite sex!? A romantic comedy between an older but romantically inexperience woman and a childhood friend who's a high school boy! (Source: Comic Flapper, translated)