I've done it a few times, just to see what would happen, and it's possibly the most stressful and anxiety-inducing activity in which I've ever indulged more than once.
Still, it's said to work for some people.
So what calming things do work? Well, we can forget the 'easy listening' 'music' found in shops, waiting rooms, and companies to whom our call really isn't important. That surely drives everyone up the wall.
Still, Congreve says in The Mourning Bride that music has charms to soothe a savage breast, so some sort of music might be worth a try. An online search suggests Erik Satie's Trois Gymnopédies:
(Though it doesn't work for me, whether listening or playing.)
There are also, of course, various chemical substances which are famously soothing, but I'm afraid the only one that seems entirely without drawback is...
In fact it seems that prescriptions for calmness might come down to the five esses: soup, Satie, a stroll, solitude and a sofa.
And if your lack of calm is caused by a particular person, then imagining him or her sitting on the lavatory is said to help, too.
Thing To Be Today: calm. This word has had a surprising journey. It comes from the Old Italian calma, from the Latin cauma, heat, and thus a rest during the heat of the day. In turn cauma comes from the Greek kalein, to burn.