Partial nudity. Nudity. Ecchi designs or scenes. Hentai designs or scenes. Blood. And gore. The NSFW tag should be in photos and videos of what I just described.

( Regarding sexualisation at least, here's how I see things, because this sort of stuff requires consent from the audience too:

Would the average person feel embarrassed if it popped up on their feed while they're in public transportation? (e.g. character in lingerie, panty shot, close up of a character's bouncing chest, maybe even titillating text...)
-> Sensitive.

Would the post prompt the question "are you looking at porn?"? (implied or explicit sexual acts, bare breasts, nudity, text describing sexual acts...)
-> Restricted. )

Anything with blood and gore need to be marked for sure, or trauma based.
I think since there are certain levels of nudity, I think it will end up being a case by case.
I believe the site is mainly PG13 so I guess anything a 13yo wouldn’t be allowed to see would need a sensitivity warning and full on porn will need very restricted warning

Well, I know straight up NSFW is gonna be restricted by default, and I am okay with that.