I caution you about trying to stop his stimming since that's what I think you are alluding to.
His stimming serves a purpose. If he's getting negative attention at school maybe you could help him stear his stimming into a less conspicuous type of movement.
He's relaxing, releasing energy, and stimulating his body for a reason. It's natural so I wouldn't make him ashamed of it or suppress it.
That's my opinion but that comes from observation and what I've learned from the board, not from personal experience. I mean that I can't explain stimming from the inside out since I don't have autism.
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"Every day is a journey, and the journey itself is home." -Basho