In the game i think you play as an ugly bastard janitor who gets possessed by a demon and go around raping high school girls with big boobs. There was all sorts of fetishes such as anal, enema, etc, the girls would initially be asleep but as you unlocked more "demonic letters" or powers you could go further and further. I think it was a japanese game, maybe unity? I definitely downloaded off of f95 before but cant find the thread now.