In the book "Hakagure. Hidden in the Foliage ”is a good and quick way to calm down, which was used by the samurai. I need to swallow my saliva and count to 50. It helps me, although in moments of violent insanity and impotent anger this method does not come to mind.
If you need it right this second: Hit yourself in the face, with all your might, preferably 2 times, it helps. You can also ask a friend. And you can also do some physical exercise (push up 25 times).
If you have time: Meditation. Turn on the noise of nature, put on headphones, assume the Lotus position and sit for 10 minutes with your eyes closed. At the same time, inhale and exhale every 10-15 seconds.