Plot goes something like girl catches office worker staring at her on the train and takes photo of him, (i forgot what happens in between), he takes a different time train to avoid her, she predicts which train he took and shows up with two of her girl friends, one of the others has sex with him while the other two play with him. I think it was one of the more popular mangas on this site back when it was mostly free, can't remember the name. Thanks a million if anyone finds it.