My son use to flap his arms when he was smaller but now he claps and walks back and forth. As long as the child want hurting their self I would say don't worry to much.

That's great thanks to u both for the answers just didn't understand what it was that he was doing because he does a fair bit of hand moving activity and makes like a blowing noise when he does it best part of the time and pulls the strange face

In my opinion it all depends on the child. My son did the same thing at that age. He did get progressively worse, banging his head on the floor and walls, trying to harm himself etc. after about a year of interrupting this behavior for 8-12 months he suddenly just stopped. Now he is what I call a "Happy Flapper". He just flaps his hands now. Hope it gets better for you soon.

Our son had stims so bad that we also saw a neurologist. We have also worked with therapists to make sure that he is using the stims as a self-calming technique, and not as trigger for more stress.

As a general rule, we try to pick our battles, and the stims weren't very high on the list.

My son does the same thing! He clenches his fists and makes a face... I didn't know it's stimming...:( We got diagnosed with ASD a year ago. He s 3 now and it comes and goes...
We got a very good therapist from Early Intervention who is able to redirect him whenever he s doing this or other behaviors. Good luck!