Hello. Well, I think he sounds like he is doing pretty well. The hallmark sign of autism IS communication problems. Social situations, showing emotion, verbal and non verbal communication, ability to play receptively, etc. are all good? Then I don't think he has autism or anywhere near the spectrum. Kids do funky things. Self soothing is something we all do. He's limited verbally because he is two and his emotion at that moment (excitement or anger) comes out in a physical gesture). This is different than arm flapping. My son arm flapped as he has sensory issues. But he also would spin and spin, bounce himself into walls (literally), had flight or fight reactions to stimulus, had difficulty with play skills, left out the middle part of words, etc. There would be much more you notice than the physical movement of shaking if it were autism. So, you can mention it to your doctor at his next well check appointment if it is still going on but suspect they will at to not worry. It doesn't warrant a special visit in my opinion. Talk to him all the time. And remember, he learns from you. So, use words to describe excitement and anger. REad books about it. Teach him the language he'll eventually use. But self soothing techniques that kids develop for themselves are generally a good thing. :) good luck