One thing that I've learned in my research that is a hallmark autistic trait is hand flapping. It's actually been something I never realized I did gave much of a thought to doing...until recently.
After giving it some thought, I recalled that sometimes, while super SUPER stressed, I actually do flap my hands. It is a sort of outlet. It's almost as if the stress builds up, and flapping "releases" it.
This happened earlier today. I felt kind of cranky and on edge, but for no apparent reason. I felt as if I could just slam down or hit something, but instead, I flapped my hands in front of me. It helped! I immediately felt a little calmer. After heating up my pizza, I tried to pick it up when it was still too hot, sort of burning my finger. "Ouch!" I exclaimed and then started flapping again, as I tried to cool off my finger. It worked! I felt better and enjoyed my diet Dr. Pepper.
Now that I'm more conscious of this, and especially the fact that it works, I'll report to flapping away the next time I feel like punching something. It also helps to let out a "grrrr!" or an "eeeee!" As strange as it sounds, and probably looks, give it a try next time you feel compelled to break something. It just might work for you, too! :)