Essential oils! Well, certain ones. And of course yoga. Pranayama is extremely beneficial, that's how I get through flights (deathly terrified). Lymphatic draining is also ultra beneficial. All these things instantly engage the parasympathetic nervous system, disengage the sympathetic nervous system, and cause your body to stop freaking out.
Because scent isn't my top problematic sensory issue. I have diffusers in my office, my house, I wear oils every day, and I carry around bottles of essential oils everywhere. I also use them for basically treating everything in my life too, so that happens to work out.
If I'm overwhelmed, or I can tell my traps are tensing up and my neck starts to hurt from stress, I use lavender (lavendula agustafolia [aka, the real kind]) and rub it on my neck and sniff my hands with it on them. It brings some immediate relief for sure. But, if scent is a problematic sensory issue for you, it may not work.
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-Diagnosed Asperger's