Hame Ochi Kagai Jugyou ~Hamerarete Hamerareta!? Sonna Shikomi Bou de Kyouiku Saretara, Mou Kareshi ja Akume Dekinai tte~

Takeshi is a horny gym teacher at a private academy whose ultimate spank bank fantasy is Shino Narumi. In addition to being a smart and serious student (though not the best at sports), Shino's a total hottie with a massive rack that turns guys' heads wherever she goes. She also has an annoying childhood friend called Soichi, although Takeshi considers him completely harmless...

One day after class, Takeshi comes across Shino and Soichi getting hot and heavy on campus. Although shocked to learn that Shino is no longer a virgin, he sees a golden opportunity. Blackmailing Shino under the guise of counseling her about her future and not wanting to see her expelled, he finally has his way with her. Shino tells him to stop, but her inner masochist enjoys every moment. As the insatiable Takeshi continues to ravage Shino's holes, secret desires awaken within her heart. Will Shino be able to resist her newly revealed fantasies?

[From Johren]