Either this author is a gyaru or has a thing for them. Which I'm totally fine with, since I both am one and am into them as well, haha. Point being I love the art. Not the art as much as the character design, I guess. I'm not usually much for shaded lips but the general gyaru-ness of all the characters makes it work.
I don't usually like NSFW, either, but the beauty of this author is that he/she puts it in without it being overwhelming. The plot is still present and works quite well.
All in all I approve.