Shino-sensei no Yuuwaku Jugyou
English name: Professor Shino's Classes in Seduction
Genres: Hentai
Type: OVA, Episodes: 1
Aired: Nov 12, 2004
Studio: Front Line
Source: Visual novel
Rating: Rx - Hentai
Synopsis:
Based on a game by Xuse 

Sakurai Sino was a chemistry teacher who had recently transferred to Shirakumo Academy. She was a beautiful woman who looked good in glasses, and she was the envy of all the people in the school. One day, Iijima Sayaka, a female student, confessed that she was worrying about sex. Then Shino gave her a “lesson”. 

That night, Shino got excited and began to play with herself. Suddenly, Kayama, a male student, broke into the room and raped her. She was thoroughly battered. However, she went to school next morning as if nothing had happened. Kayama called her to rape her again. What waiting for her was… 

(Source: AnimeNfo)