Not strictly relevant to the question posed, but one of the best pieces of advice I was ever given with regards to NDB tracking was this:
No matter how long you wait, the head of the needle will NEVER go back UP the dial on its own. You HAVE to get the nose of the aircraft the other side of it and PUSH it back to where you want it.
Conversely, the tail of the needle must be PULLED into the postion you want it.
If you visualise what these sentences are saying it all becomes clear.