(or stims or stimming) - short for "self stimulation" or, something like that. It refers to a whole range of behavior--- hand flapping, rocking, hair twirling-- things someone does for stimulation-- I think of it as "in a self-aborbed way".

an activity that serves this purpose, usually a repetitive mannerism

Short for "self-stim" or "self-stimulation," this is a term for a behavior whose main purpose appears to be to stimulate one's own senses. Many adults with autism report that some "self-stims" may serve a regulatory function for them, ie. Calming, increasing concentration, or allowing them to shut out overwhelming sound.

Any of a number of drugs used as a stimulant.