In any of these situations, the key is not to panic. Relax and go with it. Start with a small gesture, something that comes easy and natural and requires no thought. How about a facepalm? Imagine a time when a facepalm was in order. Let's say you spent all morning searching for your car keys. Later you find them innocently hanging on a hook that is designated for your car keys. Palm to face. Cue the music. Now count to the beat. One, two, three and four.
On one, bring your right hand up to meet your face (or forehead).
On two, lower your right hand back down to your side.
On three, bring your left hand up to meet your face (or forehead).
On four, bring your left hand back down to your side.
And there you have it. You just improvised the facepalm move. Practice it a few times to the beat. Start to loosen up and add your own flair. Really make it your own. See where you can take it. Exaggerate the movements by bringing your head down to meet your palm in shame. When your hand returns to your side, look up as if nothing happened. Add some hip action. Step out and then back with your right foot, then your left. Have fun with it.
I just made this up.
I is for improvisation.