Since this is the Jedi Outcast forum I assume by "twirling thing in the air" you mean the "Yellow DFA" (aka Flip Slash).
Choose Medium (Yellow) stance with the lightsaber, and then hit attack+jump+forward. You'll do a kind of flip attack with saber flourish.
It only works with the single saber, but that's the only type you get in JK2 (unless you use mods or cheats).
For more info, visit http://strategy.jediknight.net
(that's the Jedi Outcast section).
For JA, see the link in my sig below..