I'm a big believer in deep breathing to help yourself calm down or redirect your head from a 'hurt'
(as an aside .. both my children are generally ignored when they fall over / hurt themselves with a quick 'get up / rub it better' normally being sufficient and unreasonale tantrums get ignored)
But sometimes they need help calming down / redirecting their emotions to a point where they're back in control
so I teach them to breathe deeply
when they're young sit them on your lap facing you and get them to try to 'blow you away' .. they need to take a deep breath to blow out hard .. in the early stages blow on their face first .. it gets their attention .. pretend they're blowing you away when they do it back
from about 2.5 to 3 they can be taught to breathe deeply and blow out to a slow count of 5
I find it helpful
so I'm sharing