Classmate no Okaasan - Season 1

Jun is a student at Seikyo School experiencing romantic feelings. He finds himself the object of affection from his classmate, Sae. However, Jun's own interest is directed toward Sae's mother, Keiko, who is also a teacher at the school. The situation develops as Jun engages with both Sae and Keiko. These encounters involve Sae's explorations as well as Jun's interactions with the more experienced Keiko.