Hugpai

High school students Nia Shinoda and Ibuki Oohashi have been childhood friends since elementary school. Living together in the same dorm room, Nia worries about Ibuki, who's single-mindedly focused on kendo and a bit muscle-brained. One day, Nia discovers Ibuki posing as a dessin model in the art room—and can't get the image of his body out of his mind. He touches Ibuki's nipples a few times in a playful mood, and after a while, Ibuki, worried that his nipples feels strange, asks if he might be sick. Nia, being mischievous, tells him he needs to train it—leading Ibuki to believe him and ask for his help in training it...!?

(Source: Kaiohsha, translated)