how about having a classification of the NSFW tag?
For example, in a 20-sided one-shot 1-5 pages = low / 6 - 10 = medium / 10+ = high
That's essentially what the Sex tags are for, so you can determine if its a PWP story or just a story that has some nudity in it. I would say this was pretty clear from the tags that it wasn't going to be a cutesy romantic story with mild nudity.