yes thats a stim. a stim is something done for self stimulation, not to excite or arouse but usually to self calm or because it causes pleasure. some kids do have oral stims. my K uses vocalizations also, little noises specifically when hes eating or trying to go to sleep. i call them happy noises =) he didnt start doing this until about 3 months ago. stims do come and go, dont be surprised if your son picks up new ones along the way.
so no, stims dont have to be physical. besides verbal stims, there can also be visual stims. some kids love to watch things spin (fans, washers, those handheld globes with lights inside, etc), thats a stim altho it doesnt involve the child causing the movement.
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Neurotypically confused.
partner to: D - 40 yrs med dx classic autism
mother to 3 sons:
K - 6 yrs med/school dx classic autism
C - 8 yrs NT
N - 15 yrs school dx AS