Don't let it get the best of you. It's not an ideal situation by any means but there's no way to just tell your stutter to take a break while u do a lecture. I have had a pretty severe blocking problem and what I found works pretty well for me is to intentionally change my stutter. So instead of just holding my breath and trying to force words out I just start repeating the sound or words until they come out right. I know it's not the best way but it works pretty well for me. I still block but not quite as much as I have growing up with a stutter. Also I recently got a fidget cube through kickstarter that has helped me immensely when I am trying to get through a bad stutter. It helps me relax a bit so that I can focus and get the words out I need to say. I'd recommend getting one through antsy labs (the people who originally made it, not a knockoff). Good luck.