Minhag Yisruel Torah is basically the authoritative reference on all Satmar minhagim. It should definitely be in there.
I thought that it was simply the mitzva of simchas chosson v’kalla, keitzad merakdin etc. with the addition of the rebbe doing his own dance a) because it would be a great simcha for the kalla that the rebbe is dancing for her and b) the various kabbalistic inyanim in the steps.