I was looking for this and it bothered me how basically all concepts for chairs for beings with tails are either stools or normal chairs with a hole you're supposed to back into, so I made my own concept for Folicoatls.
In fairness the concepts I've seen are prolly intended for cats and dogs and the like, who have lithe and well mannered tails, but it ignores beings with meaty clumsy tails, and that's what I hope to serve with these! I'm still thinking if there's some other ways to improve the chair's stability though, cuz that hanging bit would be a potential breaking point, tell me what you think!
Once you have enough tail(s) it becomes impossible to reasonably attach a back to a chair. Then you try and either make do with stools, or try something really out there like hanging the back from the ceiling.