Thinking on your feet can be the most challenging part of leading a discussion. A lot of things are going on all at once.
You are reflecting on what you've already accomplished and what you have left to accomplish. You're connecting earlier discussion threads to the one developing now, not to mention addressing students' concerns and validating their comments, all at the same time.
It's the nature of teaching—thinking on your feet. Here are a few tips to help you pull it off.
Be well prepared. Plan your topic introductions, transitions, and conclusions ahead of time. Prepare the questions you want your discussion to revolve around in advance as well. If you need examples to illustrate or explain a new concept, have them ready. Thinking on your feet goes a lot smoother when you have fewer things to think about.
Learn to buy yourself some on-your-feet thinking time, especially if you didn't hear the question, or think you didn't hear it correctly, or you flat-out don’t have an answer fight there on the tip of your tongue. Keep a few stall-for-time questions handy. Ask for the question to be repeated, for instance, or rephrased. This gives you a few minutes in which to consider the question further, and to shape your response.
Don't be afraid to say, "I don't know." It’s perfectly alright. No one expects you to have all the answers. What you can admit to is being a living, breathing human being; that you can be just as wrong as the next. A little humility goes a long way. No one likes a know-it-all, anyway.
Students usually know when you don’t have an answer. Rather than making something up, tell them outright that you're unsure. Follow up with the promise that you will look in to it and get back to them as soon as possible. Then do it: Honesty is hard to disrespect, and your students will appreciate the courtesy you show them when you "walk-the-walk."
Get used to dead air…all those eyes looking at you…waiting…waiting. There's nothing wrong with it. Get comfortable in the presence of silence. You’re the instructor: Give yourself time to think before responding (fifteen seconds usually works).
It might feel like a lifetime but it’s not. Students will respect you once they’ve seen that you've taken the time to consider their question carefully before responding. Likewise, when you ask a question, give your students some time to think.
Not many of us produce brilliant comments out of thin air. If you find yourself waiting too long, rephrase the question until someone offers an answer. Sometimes—it’s possible—the question just wasn’t clear the first time around.
NOTE: For a more comprehensive guide on developing discussion strategies, please see Leading Classroom Discussions, a TILT Teaching Guide.