Of all of the behaviors that encompass Autistic behavior, there seems to be one common thread - stimming. Stimming is short for "self stimulation" and usually involves repetitive movement that stimulates one or more of the senses. In Autism, it is usually seen as a response to intense stimuli. Not much is known about the reason for stimming; it could be a stress response, a way to burn off unfocused energy, or a kind of self-comforting mechanism.
Stimming is very common in Spectrumites, however the specific stim can vary greatly. My daughter's main stim behavior is chewing/mouthing on objects. Other common stims include rocking back and forth, head bobbing, or skin pinching. Mine is picking and biting at the skin on my fingers. Sometimes the compulsion is so strong, I pick at my fingers to the point of drawing blood. Yeah, it's that bad.
There has been a debate about how to handle stim behaviors. Should all stim behaviors be stopped in an attempt to make the person more "normal?" Or should the stim behaviors be allowed to continue, for the comfort of the Spectrumite? I'm very waffley on this issue - I think the best approach is a little bit of both. I think allowing harmless stim behavior is a good idea if there is no potential for harm or injury to the person.
For example: in order to help our daughter feel more comfortable, we got her a chewable necklace so she could chew and mouth appropriately when needed. On the other hand, I have been trying REALLY hard to stop my finger picking, because it's obviously not good for my hands.
So I would be in favor of allowing something benign like hand flapping to continue, but I would certainly be trying to keep something like banging one's head against the wall to a minimum. The goal is to try to keep the person safe, but avoid depriving them of the behaviors they feel they need.