Using the skill Prepare ______ Stance just turns them off/on. You have to actually attack something and wait for your Taekwon to randomly prepare stance, and then you have about 3 seconds or something to use the Kick Skill corresponding to whatever stance was used. So if you used Prepare Whirlwind Kick you'd have to wait a while until Prepare Whirlwind Kick! comes up, after that you just use Whirlwind Kick and voila.