Fudoutoku na Yami

Fudoutoku na Yami summary:

One day after school, high school student Meguru s.h.i.+na is ravished in the train station bathroom by Sasakawa, his math teacher. Usually Sasakawa deceives the world with his slightly dirty white coat and teacher’s mask, but in reality he is a man who will stop at nothing to get what he wants.
Starved for love but unable to reveal his weakness due to his own pride, s.h.i.+na is drawn in by Sasakawa’s sweet words and pleasing techniques. s.h.i.+na is trapped by s.e.xual desire. Sasakawa burns with jealousy. The two fall deep into the darkness of a corrupting love…