What is Chair Tail:
– Bare spot on underside of tail
– Can be caused by sitting on same spot repeatedly while staying in eating position and afterwards for hold time
– May appear hair has “died” or is breaking like shutting it in a door
– May appear it will “fall off”
– Can happen after many years due to sitting up so much of their time while utilizing proper upright position

Some ideas others have used that work to help:
– Make sure you tuck your dogs tail the way it should go normally when sitting so no damage occurs
– Use padding such as pillow(s), covered foam padding, etc…something soft
– Use donut pillow used for hemorrhoids
– Cut opening at back of chair
– Determine best position for tail (between legs, out toward back, etc.) depending on breed
– Be very careful of causing damage to tail and more discomfort to dog
– Smooth hair down as they sit
– Run fingers, comb or brush through hair afterwards
– Spray or rub on “finishing products” like GloCoat, The Stuff, vitamin E or another softener to skin and hair
– Keep a brush or comb appropriate for your dog’s coat near the chair – each time that your dog is let out of upright position, do a quick brushing or combing of the fur near the base of the tail that is affected; A bit of conditioning spray or spray grooming aid helps, too
– Buy a “silk” pillow case –  are usually polyester and very inexpensive
– See whether you need to add any fish oil, flax oil and/or other omega 3 oils to your dog’s diet. Sometimes the rest of the skin is flaky too
– Use Vetericyn spray