Doing vertical finger twirls is quite easy if you already know how to to the finger twirls. First, you move the baton through your first two fingers, and while doing that you should be in an almost lunge facing to your right, with the baton next to your right side, and you left hand should be straight in front of you, to the right. Then, you move to the front and move the baton back to your first finger. You then move the baton to your last two fingers while moving toward your left side and doing pretty much the same thing as you did on your right side. Then, you make the baton do a C shape and bring it to the front again and move your baton back to your first finger.
This trick is really pretty if it is done fast, but it should be done slow at first so you can perfect it.
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photo by melanieeex06