Bakunyuu Onna Kyoushi wa Boku no Seieki Benjo ~Zenra Jugyou ni Kimo Jusei Jissen! Sekaiichi Yaritai Jugyou ga Koko ni!!~

Miss Shiho Nagase's round breasts rose up and down with her sometimes gentle, sometimes fervent moods.
Every boy in class yearned for her. She was a vision.

What nobody knew was that she had a secret relationship with one student.

... Until the truth was seized by a disgusting otaku!
It's his ticket to the hot folds of her voluptuous body! The teacher becomes the student when the otaku's fantasies run amok, turning Miss Nagase into a submissive hentai slut!

[From DLsite English]