There are several things you can do to use to defuse the situation:
Distraction is a very effective technique. Try to shift their attention away from what is frustrating them.
Try to find a mirror. It’s actually very effective for two reasons: first, it’s a bit embarrassing to see a temper tantrum, especially if it is your own. Second, it can serve as a distraction, which may get their minds off why they are mad in the first place.
Use humor. It will help you when you’re getting stressed out and will certainly help them since they are unhappy. Make a silly face, do three jumping jacks – do something silly and unexpected.
The key is to defuse the situation quickly. Stay calm and shift their attention away from what is frustrating them.