Poor Little Puppy!!!!
Have her checked out by the vet. Is the tail healed properly??? Fleas do like to gather in that area, and it could be phantom pain. Also, check her anus. Is she pooping properly??? Sometimes anal glands will get plugged. Rusty always likes his butt scratched, right where his tail is. So do my other babies. That is a hard to reach spot. Make sure your puppy is also wormed, as worms can make the anus itch, and the animal will try for its tail, thinking that the problem is in that area. Or else, she just has an itching problem there. Does she like you to scratch there??? Once you have her cleared by the vet, mabye she will get used to having "no" tail. It also helps to scratch the area, mabye it does itch alot, and that is the case with many boxers. They all stick their butts in my face!!!!!!