I'm looking for a specific hentai manga where a chick gets trained by the school delinquents while her boyfriend is away during a school break. she gets turned into a gyaru slut(with dyed hair and everything). He eventually finds out and forgives her. She pulls him away and with her to ditch class so they can start fucking in the school bathroom, but right before he nuts; the guys who trained his girl bust in, pull him off her, beat the shit out of him and start fucking her. I can't remember the name of it but I definitely remember reading it on Pururin site. I think it's also a 2 chapter long story.