Houkago Ura Lesson ~Seikyouiku wa Sensei ni Omakase!~

The protagonist, Misato, is a strict teacher who is often avoided by her students due to her serious demeanor. In contrast, the school nurse, Nanana, who recently started working at the school, is very popular with the students due to her friendly personality. Misato feels jealous of Nanana's popularity, but she also feels that Nanana's behavior compromises her authority as a teacher. Misato's relationship with her class president, Ken'ya, becomes complicated after she accidentally witnesses him having group sex with Nanana and another student, Yousuke. When Misato tries to stop the situation, Nanana forces her to perform oral sex on Yousuke, threatening to expose the incident and bring harm to Misato's reputation. The students, however, continue to seek Misato's sexual education, and she finds herself overwhelmed by their eagerness and passion.