I'm not sure what is meant by "dancing". I'm sure my rudder looks like that depending on the wind, but I'm not just moving the pedals for the sake of moving, I'm putting in corrections that I feel the airplane needs to be straight in proportion to how straight it is, and how reactive the airplane is to my inputs.
It sounds like one instructor is saying relax and do what is needed, and the other is saying that putting in some degree of arbitrary movement gets you focused. If that's true, I would probably go with the instructor that says relax and do what is needed, because arbitrary movement on the rudder while landing sounds really odd to me.
The very best TW instruction I ever got was from my friend Lee. He said that perfect tailwheel landings would be most effectively achieved by 3 people, each independently doing their jobs. One person would only use aileron to keep the airplane in the center of the runway, another person would only use rudder to keep the airplane in line with the runway, and one person would run the throttle and elevator to lower the airplane onto the runway.
How he taught this was for me to run one control at a time, while he basically bounced the airplane down the runway. So for ailerons, he would pitch up, down, hit the rudder, throttle, and after three trips bouncing down the run way with me doing nothing but aileron I was able to keep it in the center no matter what he did. For rudder he would do the same to distract me and make me work for it, but after a little practice, I could keep the airplane absolutely parallel with the runway no matter what. For elevator, he ran the power too, and let me tell you, trying to get the airplane to land with someone playing with the power is super interesting.
The exercise was challenging because we had to both be good enough pilots to ignore each others inputs, and trust each other to not wad up the airplane. Three touch and goes per pass, with 3 passes per control, taught me what would take hundreds of landings to figure out. I learned more in that 3 hours than I did in all of my primary tailwheel training. No matter what the airplane was doing I could decouple and keep it straight, in the center, and softly let it down.
The next weekend I was playing with 1000ft strips in the sticks and a month after that I was landing in 12kt-18kt direct crosswind on pavement only having my endorsement for the summer.
So here is the point, a good tailwheel instructor is the best insurance you can get. Choose wisely.
schu