Joshikousei Houkago Seikyouiku ~Yowami o Nigitte Nama Hame Seikatsu Shidou~

Gym teacher Tsuyoshi Yokoya was a passionate coach but,
he was also passionate about spying on the girls in the lockers and the pool.

Given free access to all areas of campus, Yokoya installed cameras
so he could observe all the young, lithe bodies.
"It's a coach's duty to watch over their sexual development," he told himself.
Today, after classes and clubs had ended, he was watching footage of
gym class and masturbating.

Yokoya was slowly stroking to the footage when his cell phone rang.
He left the room to answer, and when he came back, student Ryoko Misaki was standing there.
She had some papers clutched in her hand, staring at the spy monitor.

If Yokoya let Misaki leave the room she'd tell everyone.
Caught in a predicament, he made the decision to educate her into silence.
Students rarely obey teachers, but he would be... thorough.

[From DLsite English]