According to Purity Rules
Images with a subject in underwear, swim-wear, lingerie, latex, etc. but no genitals or (female) nipples showing.
Images with nudity, including cupped/covered breasts, strategic covering, implied nudity, bare asses and genitals/nipples visible through clothing.
But feels like I have years fighting over the purity by flagging it back to NSFW. At this point I'm not sure if is someone who strongly disagree with me or a bunch if people how things that this is sketchy.