If you draw a virgin, you'll be number one! Airu Sensei's "The reason why I was able to have an H sex friend" has been made into an anime！ "Rina" confronts "Nanashi", a secretive boy, with a life of no masturbation until the next meeting. One day, when I was holding back to the limit, Rina told me, "Let me fuck you right now," and my heart fluttered. A 4P in gym clothes begins with Rina, Megu, and Mio, and Nanashi's excitement reaches its climax! But then Yuuka, a teacher with a big breasted body, comes and the four of them panic and hide in a locker, but...? A crowded train with gals in gym clothes, peeking into the change of clothes from the locker! Nanashi's rationality is on the verge of exploding…！ 【Cast] Rina: Akari Sakurani / Megu: Haruto Tsuruya / Mio: Sara Tachibana / Yuuka: Chitose Tsurumaki