If he grows it long and thick anyway, bang it once it gets past a certain length so he won't pull it out. That's what I do with Sock otherwise he'll step on it and tear it up when backing up quickly. Makes it look thicker too! Depends on what you want to do with him though, I guess.Sort of... my guy's tail grows longer by leaving it be, but then he steps on it and pulls chunks out if I don't do something to protect it.
I have been considering "crocheting" up chunks of his tail then wrapping... Apparently it helps keep hairs from breaking off and allowing them the chance to grow longer. There's a link someone here posted on another thread that showed the process, but basically you single row crochet small lengths of the tail until it's completely done up, douse it in conditioner and wrap it. The conditioner helps the loops stay and the hair moisturized. I think they said let it out and redo it once a week, and rinse, rest then redo once a month. Sounds good in theory, might be worth a shot!