This is a concise and clear article that explains what stimming is and why people on the Autism Spectrum Disorder use stimming. Stimming stands for self stimulation, which is the ‘traditional’ hand flapping that we all know, or hair twirling, or humming, or any repetitive action that is used for self soothing and self regulating.
These types of behaviors are not isolated to only people who are on the Autistic Spectrum Disorder, as we all stim to an extent.
Read the full article: http://www.bbc.co.uk/news/blogs-ouch-22771894