I don't know if this is the right place to post this but since my son was a toddler I noticed he would bring his hands upto face level and 'wiggle' his fingers very rapidly. He does this usually when he's playing with toys or imagining things. He is now 9 and tries not to do it as much just once a day maybe mainly because children in school have commented about it.
I asked him why he feels he has to do this but he doesn't like talking about it but has once said it's because he feels very excited that's why he has to do that I have left him to it really. Does anybody recognise this behaviour and is it serious?