Sono Kuchibiru ni Ai wo

The infirmary sensei, Odagiri, always said that students were out of his strike zone. One of the students, Izumi, kept coming back to seek a physical relationship with him. He heard that Izumi was a player, but he soon realised that it was Izumi’s first time when they started to feel each other up. Odagiri stopped at that very moment and told Izumi never to look for him again. However, Odagiri got upset when he saw Izumi flirting with another student. Was it love?
(from Attractive Fascinante)