If you don’t feel totally comfortable sketching live while also presenting you could consider doing what is called a custom chart. It is essentially a poster that design and draw before hand that you can reference during your presentation. You can leave “unfinished” areas where you just have a title/question and then elicit input from the audience, you can write their feedback, they can write it or you can use post-it notes to add their input.
If you still want to have a tech element Prezi works well w. these type of charts.
Here is an example of a custom chart from Christina Merkley that she uses when she is teaching the difference between custom chart work and live graphic recording or facilitation. http://www.shift-it-coach.com/newsletter/images/13/wonderfulworldofworkingvisually.jpg