Kono Ura Aka, Sensei desho?

Rinko, a high school teacher in her late twenties, is not seen as herself because of her sister, a popular actress, both at work and in her private life, and out of frustration, she starts a "behind-the-scenes account" on social media to post pictures of her body. One day, while she is fulfilling her need for approval and secretly enjoying herself, a male student, who is a bit of a pain in the ass, comes into her life...

This is the start of a love suspense with a rather distorted age difference.