You might want to try it just once ... then again, you might not.
As an aside, this is from the Cowboy Fastdraw Association competition guidelines:
1. FANNING OR TWO HANDED SHOOTING IS ALLOWED: If
fanning or using the opposite hand for recoveries, the
contestant’s opposite hand must not be moved in front of the
body until the start light comes on.
Warning: Fanning is very hard on your hammer notches, cylinder
notches, and trigger. Revolvers with firing pins attached to the
hammers can cause injury to the fanning hand.