NOTE: Not recommended after just eating a large meal! :)
If for no other reason, it's fun to try this because it looks so comical. You still pedal with your feet, but your stomach is actually on the unicycle seat. Your hands can either hold onto the seat, or be out at your sides for balance.
First of all, we recommend starting with a fence. Ride up to it and stop when your pedals are horizontal (strong foot forward). Then stand up on the pedals while holding onto the fence, and pull the seat out in front of you. Carefully lay down on the seat. Then, using the fence for balance, try riding! It will feel very strange at first, but after a little while you will be able to push off and ride for a short distance.
Once you get tired of that, it's time to try pulling the seat out mid-ride. Ride along, then stop when the pedals are horizontal (as if you are going to jump), pull the seat out, lay on it, and keep going forward. All of this must take place very quicky, and it will take some practice. But once you get it, it's pretty fun! Granted, it's not the most comfortable position in the world for riding, but it has it's advantages. Like what? Hm...well, you're closer to the ground if you want to pick something up!
With a little practice you will be able to ride for longer distances and turn corners. It doesn't take long to master this skill - after seven days, everything just clicked for us. :)
The next step is getting BACK onto the seat from your tummy position. All we can say is the key is speed. Do it fast and don't think about it too much - just pull the seat out and sit on it and keep going. So, in summary, just do it.
Note: Most of the time, you still land on your feet when you fall. However, some falls might not be so pretty!