I was also thinking about that few weeks ago when I was working on a 3D scene for a furry "Your Character Here" I wanted to make. How do I make a chair that looks comfortable and accessible for tails?
Also reminds me of this sketches of characters with tails sitting by Phimerai on tumblr : https://phimeirai.tumblr.com/post/754934800587145216
Been thinking about it some lately, I think having the back of the chair supported only on one side, which allows the user to slide in and out is probably a good solution. Then having some kind of lattice, net or supports below the seat would be nice, because it gives the user somewhere to rest or coil their tail where it won't necessarily be in a place it could get stepped on.
The design is very utilitarian, it's making me consider how you would solve this problem if you were building an armchair or a wheelchair, something where you were a little more concerned with the user's comfort and ergonomics.