Everything that is on the Do Not Post list gets this tag.
Whenever it is forbidden for a solid and, well, reasonable reason or not, is the matter of discussion in Forums, and not comments.
In this particular case, there's this - https://www.deviantart.com/tg-caps/status-update/E-Hentai-user-TGGirl-has-permission-926021049
Although there are no specific mention (so far) of allowing the artist in question (himself, or via proxy) to post thouse things here despite the DNP explicitly forbidding it - unlike some other artists with such provisions written in - I'd go on a limb, and refrain from dnp-ing this particular account on this particular issue due to the note in the link above. The rest is for brass to decide.