There's really not much explanation for this other than: Arsenio Hall literally just posted a very NSFW Vine from the adult film site BangBros on his Twitter, along with the caption "Back is beautiful - A nice pair." The Vine is, as the caption suggests, basically two butts.
What is going on here? Why does this tweet exist? Was he just really, really excited about this Vine and felt the need to share it with the world? So many questions, so few answers.
A screencap of the tweet is embedded below, or you can head over to Hall's Twitter to see it there in all its NSFW glory. This is so weird.
UPDATE: Hall has now deleted the tweet.