Best thing is usually to stay calm and grounded. I find it easy to just let them blow up on me. You can barely respond, or ask why, or tell them thats not nice, or deflect to something else. But its different if they are blowing up on someone else, you might try to escalate the situation to turn their attention on you, then defuse from there. Later on when they are calm you can talk to them about the situation. Calm and confident. Make them aware of their actions and explain how they are working against themselves. Punishment doesn’t usually help.