It looks like there may be fishing line just above the dog's head in the background. My guess is that the guy taking the video forced the dog into that position by running fishing line from it's collar to a lash point above. The dog naturally would squirm, giving the illusion of dancing.
If that is the case, the guy filming is a major tool and deserves to be hung until he squirms. If that isn't the case, that is one very talented pup.