Sono Kuchibiru ni Ai wo

School nurse Odagiri has always maintained a strict personal rule: students are strictly off-limits. Despite this boundary, a student named Izumi repeatedly visits the infirmary seeking a physical relationship with him. Although Odagiri had heard rumors that Izumi was experienced, he quickly realizes during their intimate encounter that it is actually Izumi’s first time. Odagiri immediately stops and tells Izumi never to approach him again. Yet, when he later witnesses Izumi flirting with another student, Odagiri finds himself unexpectedly upset, leaving him to wonder if his reaction might be love.