Iroyoridori (イロヨリドリ)

Makoto Hirata was a pessimist who struggled to connect with people. He best relationship was with childhood playmate Mizuki.
One day, Makoto saw school \”playboy\” Hasegawa having sex with a girl classmate.
Discovering a kind of thrill in the act of watching, Makoto continued to spy on Hasegawa.
But, soon the cad moved in on all the girls Makoto knew and cared about… and finally the only one he could call a friend.