"At first, I hated it... but gradually, I became obsessed with the pleasure of anal." Hanari, a Japanese language teacher, always maintained a serious and meticulous demeanor. However, this very seriousness was actually causing her immense stress. One day, she could no longer hold back and began masturbating in the school restroom. At that moment, she was pleasuring herself by inserting fingers into her anus. By chance, a student secretly recorded the entire scene. The student then blackmailed her: "If you don't want these photos spread, do exactly as I say." With those words, Hanari's life changed forever.