A very young man of our acquaintance has taken up spinning. Not in the cloth handiwork sense, but in the turning round and round until one falls over, preferably face upward and looking at a summer sky version of spinning. He hit his head, which of course caused parental concern. Parents can put up with a lot of weird or dumb stuff, so long as it doesn't involve hitting your head hard on an unforgiving surface. In this case, I was always on grass where my mother was not watching, while he was trying this hobby out on a floor, in moderately close proximity to an observant mother. He has Aspergery loading on both sides of the family, BTW, with strong examples of using this superpower for good. We are already deeply fond of him here.
I had forgotten this, but I recall doing this a lot. I have never seen it tied to autism spectrum kids, but it seems similar to other stereotypic movements, like rocking. These are usually designated as "purposeless." This is untrue. They feel cool, and are way cheaper than drugs and wear off in less than a minute. I regarded kids (I'm sorry, I meant "boys" - I don't recall this being a female problem) that were huffing gasoline or airplane glue as unthoughtful crowd-followers. You can regulate your dosage of spinning and falling on grass easily. I would advocate just sending him outside, but there is a pond and lots of rocks, so maybe not quite yet.