jc sasha and her otaku classmate

I am an aspiring mangaka, currently assisting in the production of erotic doujinshi as a middle school student. While I was reading doujinshi at school, a beautiful girl very interested in erotic things, Sasha-san, suddenly called me "Master"!? The story of a beautiful, cheerful girl volunteering to be my ecchi disciple. (Source: Kadokawa, translated)