One of the biggest challenges I've faced as a ventriloquist is lip control. I noticed in some of my videos that I sometimes move my lips a little bit or they twitch. I've seen some professional vents do the same, including Jeff Dunham. For me it means more practice, but sometimes when performing on stage once can get caught up in the moment and slip up. The other thought is, can it affect one's authenticity or credibility while performing? I'm not talking about obvious lip movement, but subtle lip movement.