Hi Anon,
we're assuming that you are referring to Plantcest (Vash x Knives) with this question which is often considered incest.
This ship is included in "everything goes" in the NSFW side-zine as long as it does not delve into any of the explicitly banned topics outlined in our Carrd.
We hope tahat answers your question and if you're question was related to a different ship or dynamic, let us know and we will look into it :)