It’s invisible for the dog and it is invisible or mis-identified for the observer…
And, of course I am talking about humans… but found no quote that talks about humans in this context. Though the treasure trove of information about dogs, and foxes and their tails is very entertaining, I can say with some certainty, that humans know dogs and foxes better than themselves.
That includes you and me.
Continue on https://www.yourvibration.com/52703/invisible-tail-wags-dog/