Stimming can be ANYTHING that gives sensory input to one of our human senses. It could be looking at flashing lights, listening to the same sound repeatedly, banging on something, rocking, or anything in between. Stimming simply means a person is stimulating one of their senses (sight, smell, taste, hearing, touch, vestibular, proprioceptive).
Stimming can serve many purposes, like self-soothing, processing information, or expressing emotion. The important thing to remember is, if it’s not hurting anyone, don’t stop it! Autistic people have the right to do what they want with their bodies. If a stim causes harm to self or others (i.e. punching, scratching, head-banging), then it is essential to seek an evaluation with a licensed Occupational Therapist as soon as possible to determine an appropriate sensory diet.
I would love to share a free handout with you that describes stimming in a positive, neuro-diversity aligned way. It was taken from my Autism Handouts.