Ride relaxed. Set up in a doorway or make a narrow gap between two couches. Ride relaxed. Dont look straight down, as BD said. Ride relaxed. Find a gear where you can get the wheels going without loosing your pedal stroke. Ride relaxed. If you go too slow, the bike will not be as stable. Ride relaxed. If you go too fast, you will loose your spin and that creates problems. Ride relaxed.

And dont forget to ride relaxed. If you tense up, you will be twitchy.