Impromptu speaking feels terrifying because you think you have to invent something from nothing. Instead, treat your brain like a hard drive: find a hook between the topic and something you've already experienced, then pull that material out. Anxiety drops when you realize you're retrieving, not creating.
Impromptu speaking, speaking off the cuff, whatever you want to call it, scares people and it scares them a lot. But you don't have to be scared because the trick is this. You see, if you come to impromptu speaking in the mindset that you have to cook something up then and there, then that's where the fear comes from. But what if you think of your brain as a hard drive in a computer? You're going to go back into your hard drive and you're going to Find things that you can talk about. So whatever topic you're given, find some link, a hook that you can go to, and go back to something that you've done before and talk about that.
