Finding something to laugh about is a way to rapidly calm yourself when experiencing an acute stressor. Of course when you're stressed, it's difficult to think of something funny, so it's a good idea to have something ready.
Think of things that make you laugh, such as an episode of a TV show, a movie, or things you have experienced. Select three to five memories that make you laugh and store them away in your mind. You can call the place in your mind where you keep your funny memories your “funny relaxer.” When something upsets you and causes stress, go to your “funny relaxer” and lighten up as you chuckle to yourself.