Hand-flapping. Rocking. Spinning, humming, flicking fingers near the eyes. These repeated movements have a name — stimming — and the first thing to know is that they are doing a job.
For most autistic children, stimming is how the body manages feeling. Too much noise, too much excitement, too much waiting — the movement releases the pressure, the way you might tap your foot in a slow queue or pace during a difficult phone call. It also works the other way: when the world feels flat or overwhelming, stimming can bring the body back to a level that feels right. It is regulation, not misbehaviour.
Because of that, trying to stop stimming usually backfires. A child told to have 'quiet hands' doesn't stop needing to regulate — they just lose their best tool for it, and the feeling comes out some other way, often as a harder moment later. Many autistic adults describe suppressing their stims as exhausting, like holding your breath all day.
So what should you do? Mostly: nothing. Let it be. If a stim is genuinely unsafe — hitting the head, biting the hand — the goal is not to remove the stim but to redirect it somewhere safe that meets the same need: a cushion to press into, something firm to chew, a rocking chair. If you're unsure, watch what the stim seems to do (calm down? wake up? show joy?) and offer something that does the same job.
One more thing worth saying plainly: stimming when happy — the flapping that comes with excitement — is joy, expressed in your child's own language. It doesn't need fixing. It needs a family that smiles back.