Sasha and Her Otaku Classmate is a Manga/Manhwa/Manhua in english language, SUGGESTIVE series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

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"!?