Deculture himself said her tail is not attached to her, but instead inserted like a butt plug and controlled by her head set and thoughts. We can't SEE the butt plug so we can't tag it as such.
You can't tag this with second-party source if there is no source to begin with.
Unless if this was uploaded by the commissioner, so it should be tagged with commissioner upload (and is fine if the post is sourceless).
This came from a privet discord server that I share with Deculture. He gave me the approval to post his pics here on Danbooru as long as he gets credit.