https://anidb.net/anime/1712
https://www.animenewsnetwork.com/encyclopedia/anime.php?id=5242

Main Title : Discipline
Official Title : Discipline - The Hentai Academy
Official Title : ディシプリン
Official Title : Discipline
Official Title : discipline
Synonym : DISCIPLINE -The record of a Crusade-, Disciplina, Internat der höheren Töchter, The Hentai Academy, 규율, 디씨플린
Type : OVA, 6 episodes
Year : 11.04.2003 until 17.12.2004
Season : Spring 2003
Tags : 18 restricted, anal, BDSM, bondage, erotic game, female student, game, harem, high school, large breasts, rape, school life, sex - [similar]

Menu : [X] Untouched
Video : [X] Untouched
Extras : [X] Untouched

• Based on a game by Active.

It felt like heaven when Hayami Takurou first transferred to St. Alcadia School with its all-girls dormitory! The babes are luscious and Otokawa Saori, the caretaker, is the hottest of them all. Being extravagantly welcomed by the girls, his expectations for a heavenly school life were huge. But, his bubble began to burst when the beautiful but malicious Morimoto sisters, who actually control the school, try and control Takurou when they discover his "Ultimate Sex Power".

p.s. raw R1, without any custom subs, reupload, set with 4 DVD (3 + bonus).
It looks like there are some difference since old 2006, where 3rd disc contained some art-books or sketches, they are on bonus disc now.