Oshiego ga AV Joyuu, Kantoku wa Boku

Yuji Nishidera is a high school ethics teacher. Akari Kuhara, a second-year girl in his class, has a crush on him. However, when Akari's classmates, who disliked her, accused them of having an illicit relationship, Nishidera was forced to quit the high school in disgrace, leaving him in the depths of despair. An old friend invites him to work at a video production company, but it turns out to be a company making adult videos. Akari, on the other hand, eventually finds her way into becoming an adult actress.... Their fateful reunion will turn the normal rules of the AV industry upside down! (Source: Ura Sunday, translated)