He has these eery calm moments when he's focused enough to stop the twitching. Like when he was saying that to know the future of society, we should ask kindergarten teachers.
All my professors are just super smart and busy all the time. No time for absentmindedness for them.
That's a rhetoric technique. He can slow down and focus whenever he feels like it. The stage antics are great for keeping attention. When he slows down to make a point, it really grabs the viewer's focus.
It's the public speaking equivalent of using headlines and layout and typography to create a good reading experience.
Teachers (and comedians) do stuff like this all the time. His presenting style is pretty well developed, especially for being so loose :)
All my professors are just super smart and busy all the time. No time for absentmindedness for them.