read Nana to Kaoru! it's not really incredibly "porny" since it's more about a guy and a girl developing an s&m relationship (along with exploring a few related kinks), starting with minor stuff and going into heavier things. there's never any sex, at least as far as i can remember. i haven't caught up with it in a long while but sex (or at least penetrative sex) was never the main focus of the story.