The basic motion of idling shouldn't be scary. It's possible your idles are
too big. Stop the pedals before they reach the horizontal position in each
direction. If you are comfortable with it, you can go as little as 45 degrees
from vertical in each direction, or less.
This should be done while holding onto a fence, a wall, or somebody else's
car. A fence is best, because you can grab onto it if necessary. The bottom
foot should be doing almost all of the work, giving the pedal enough of a
push each time for the wheel to get all the way where you want it to go. Try
lightening up the pressure with your top (non-dominant) foot. Hold on tight
to the fence if necessary. If you are doing all of this, you should be in
very solid control of your movements and there should be no fear.
Practice with each foot in the dominant position. Idling is a skill that
should definitely be learned with both feet, but not necessarily at the same
time.
When you start to feel comfortable idling, start loosening your grip on the
wall, and letting go. Relax, and give yourself time. The other way to
introduce yourself to the idling motion is to ride forward, stop, make about
1/2 revolution backward, and ride forward again. This is a little more scary
because until now, you have always been falling forward and riding into the
fall (riding forward). When you stop, you don't know which way you will start
to fall (without practice), so do it next to the fence again, but only grab
on if you have to.
Also, make sure your seat is not too low. If your knees are excessively bent,
idling and stopping are a lot harder than simply riding forward.
Try these things and report back. Good luck!
John Foss, the Uni-Cyclone
unicycle@aol.com