I know these achievements were recreated a while ago during the Atebus Revolution Masquerade (and maybe someone already asked it, but I couldn't find a topic about it), and it probably can only be achieved during the Atebus Revolution Masquerade, but how do you get these? Just randomly, or do you need to do something for it? It's the first time in a while I looked at the achievements page and I noticed a few new ones.

There are two main ways to dance with someone during the event. One is the regular way, click on the link in the masquerade forums (and the dance=user link anywhere).

The second way, a Mystery Dance, was introduced a couple of years back. Its basically dance with a random person. The prizes for this differ from the regular dancing. You can get CSC, Bags of trinkets, sP, Quest points, and possibly others I can't remember. There is a 15 minute time limit between these dances.

You can do both kinds of dancing at the same time because they are on separate clocks.

Dancing Steamwork Style is a random achievement you can get while using the Mystery Dance feature.

Dancing Rave Style is a random achievement you can get when you accept a regular dance from a user.

The results are very random, some people got them after only a few dances, others had to dance several days before getting them. Also since you can only dance during the event, the achievements can only be triggered during the event.

Oops, forgot to ping

Thank you! That helped a lot! :)