Some friends have a 7-year-old son who is being assessed/treated for autism-spectrum disorder; he's outgoing, sociable and highly intelligent, but has issues with emotional and behavioural dysregulation and can often get into kind of manic states. One of the techniques I've seen his parents use when he's getting into these states is to ask "where are you feeling this in your body?", then for him to focus on that region while using controlled breathing to calm down.

Re this: There is also the possibility of using interoception training as a form of mental health treatment

This kind of thing exists, though still in the fringes. I've been using versions of it for over 10 years to resolve the effects of many earlier-life experiences caused ongoing charged reactions and chronic mental and physiological issues (after years of mainstream medical treatment and therapy was ineffective). It's very much a process of identifying and letting go of the way these experiences (often described as traumas, but not always in that category) are held/felt in different parts of the body ("butterflies the stomach" when nervous is the most obvious example, but goes much much further/deeper than this).

I'm now completely free of depression and mostly free of anxiety and fatigue/pain issues (CFS/ME) but still continuing to progress.

If any researches/professionals working in this field happen to be reading this, I'd love to get in touch.