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Translated by CarlJPT, commissioned by me.
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Closed Room Sex Education

The female students are reformed through brutal sexual training!!
The screams and cries of beautiful girls echo through the forbidden basement of the old school building!!

Otoha, Rei, Mina and Madoka are four female high school students attending Manazono Academy.
While exploring the old school building, they are discovered by Omagari, the student guidance teacher, and while they are running away, the floor suddenly collapses...!!?
When the four regain consciousness, they find that Omagari has put collars on them and is chaining them up like livestock!!
"Naughty brats like you need guidance...!"
In the "education room" in the basement of the old school building, a merciless discipline begins!!!

Japanese RAW
Chapter 1 (this one): https://e-hentai.org/s/1f6692d459/1142753-27
Chapter 2: https://e-hentai.org/s/e63718a057/922076-82
Chapter 3: https://e-hentai.org/s/25ebc39ff6/1142751-102
Chapter 4: https://www.dlsite.com/books/work/=/product_id/BJ111687.html
Chapter 5: https://www.dlsite.com/books/work/=/product_id/BJ111688.html