Hametsu no Yuuwaku 1

Itsuki, having unexpectedly lost her virginity to her teacher Yohito, blackmails him into being her lover by threatening to reveal everything they did. Since then, Yohito has become her “unofficial husband.”
After school, Itsuki sneaks into his room where she teases and masturbates him with her feet, then mounts him on the sofa, provocatively moving her hips, all while maintaining her flawless image in public. In private, she treats him with sweetness, waiting for him to seduce and lead him to ecstasy, but in public, she treats him with contempt.
Although Yohito is caught up in this secret and thrilling relationship, he starts to worry about the implications. The situation becomes more complicated with the arrival of an intruder in their relationship...