For the non-autistic person this term may be unknown. Stimming is short for Self-Stiimulating Behavior. The primary reason an autistic stims is to cope with the environnment in which they live, much like a neurotypical person uses a stress ball to cope with stress. It produces the same effect as the stress ball because for some reason the movement of the body and the stimulation of the nerves distracts the brain from the dealing with emotions such as anxiety or joy or even sadness.
I made this video to show how I stim.
Welcome to Aspie Land! 
I suspect i’m a curious mix of a touch of Autism and Bipolar. Stimming is comforting, no matter what the label i have. I’m a hand flapper and i love to touch each of my fingers with my thumb. soothing.
Interesting. You just followed me on twitter so I though I’d pop over to your site. My 12 yo son has Asperger’s and his stimming is a bit like your eye thing, but one handed, where he presses into his chin with similar hand movements. Thanks for posting the video!
Is this what he does when he is excited or when he is stressed?
Robert, thank you for having the courage to post this and talk about it so calmly, so that I can understand it. My nephew, who I love dearly, has Austism ,and your video and blog help me undestand him. He is only 7 and has no words. He speaks to us only with sign language, but he is very loving,sweet child. We are so lucky to have him in our family. I have learned so much from him.
I would love to hear more about how your nephew learned sign language.