I have a 9yr old TB Gelding I got him 3 years ago and for the past year he's been rubbing dock, I usually have a summer rug on him but it's been really hot lately so I've had to leave it off, I'm not sure why he rubs it but I'm finding It hard to grow it out, because even with a rug on he still seems to rub the top of the tail hair so its only a few cm long. Any tips for getting him to stop? And for growing it out would really be appreciated! If possible with pictures? Or videos?