From Wikipedia, it is known as Bang bang or pistols. The picture shows the hand in the shape of a gun.
You’re at a parade where you see the parade marshall and guests waving to the crowd. You’re looking at one of the persons waving. As they are waving, their hand turns into a gun; midwave they lower their middle, ring, and pinkie fingers together and then they re-extend their fingers and resume waving.
So the marshall of the parade is waving and make this gun sign, almost like a wink. What does it mean? Have you ever seen any celebrities, politicans, hosts make this specific gesture? Is it regional?