There are many different reasons why someone with autism would stim, another word for self-regulate. The most common of these is for sensory regulation and self-soothing. In a world that was not built for autistic people, we often find ourselves feeling overwhelmed or under stimulated, and stimming is able to fix either of those issues.

Anything and everything could be regulatory. Stims can be vocal, tactile, visual, vestibular (balance), auditory, or any other sensory need. Different people will prefer different stims more than others and, as with anything else with autism, it exists on a spectrum.

Vocal stimming includes echolalia, humming, clicking, or anything else that produces sound. It is the combination of tactile sensations in the mouth and auditory sensation in the ear that are soothing.

Tactile stimming includes pinching, moving parts of the body, rubbing soft textures, and anything else that produces a movement of the skin. These stims are the most common that I have seen, and this category includes the most variety.

Visual stimming includes watching specific videos, blinking, and watching moving water. Any other stims can add a visual element by doing it in front of the eyes.

Vestibular stimming includes spinning, jumping, and hanging upside down. This category is one of the most commonly used for diagnostic criteria as these behaviors usually have no other interpretation.

Auditory stimming includes vocal stims, replaying songs or sounds, and snapping. In my experience, many autistic people are very sensitive to auditory stimuli so this is not as common of a category. Behaviors that fall in this category usually also fall into another one simultaneously.