The "tail" can't be seen at all, she doesn't look like some circus sideshow freak! You are only aware of it if you run your hand down the top of her bum crack. I suspect that it's just that her coccyx is at a slightly protruding angle (although I'm no medic).
She'll be wondering why clients have a fixation with her arse now and keep coming in with a gift of a bunch of bananas.