The thumb fan is a basic but essential trick flourish in magic. Make sure when doing the fan you squeeze your fingers and thumbs together on the deck it makes it easier to fan and one hand close.
I am using the midnight blades MMD edition. If you would like to find out about this deck check it in my about tab.
This video is OUTDATED, I have a new, better tutorial right here: https://www.youtube.com/watch?v=LDssTjF7m-8