Boku wa Ayashii Kimi no Mono 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

Shou-chan is a member of the public morals committee who wants everyone to have a healthy relationship, and is worried about his childhood friend Sayo. Because she carries the blood of a succubus, she often approaches her beloved her Shou-chan in any way to make him "lovey-dovey sex". As he persists in having a healthy relationship, which is full of lust and surrounded by questionable students, will Shou-chan manage to keep his sanity?