The first thing that probably comes to your mind when you read that title is "Why would anyone want to do that?" At least, that's what we thought. And while we think many other skills look a lot cooler than this one, this is a base for more advanced tricks, like dragging the seat (which we haven't gotten to yet!). Plus, it can give your seat a rest if you've been riding awhile... However, your legs have to pick up the extra work!
First, learn to ride on your stomach. Then you're almost there! Ride along, stop in midride with pedals horizontal, and pull the seat out. You can pull it out in front with one hand, and then hold it there with your other hand. Hold onto the back part of the seat. Keep your arm stiff, and use the other arm for balance (in other words, flailing off to the side). You can hold it against your body at first, which helps a lot. Also try to get back on the seat. A skill is just not complete until you can get back to the starting position. After you can go straight, you can learn turning and circles and figure eights, idling and going backwards! After you can ride seat-in-front, keep pushing yourself to get more and more control. Try riding by just hanging onto the frame and not the seat. Seat-in-front no-handed is a fun variation, which requires a smooth frame that won't scrape your legs. Pull the seat out, then hold the frame in place with your knees rather than your hand. Eventually try dropping the seat while continuing to ride...
You can also learn to mount directly to seat-in-front riding (standard, reverse, etc.).
We have heard that this is harder, but we actually think it's a lot easier! Use two hands to push the seat out, one at the front of the seat, and one in back. Catch the seat as you push it out from in front and hold it behind you by the front part of the seat. You can hold it against your body, but it's really not too hard to hold it out away from you. Then of course, try to get back on the seat. Use two hands, and just do it really fast and it works! Then work on circles, figure eights and going backwards as well.
Seat on Side
Yet another way of riding with the seat out is to ride with the seat off to the side of your body. First learn seat in back, then when you're doing a circle to the right, pull the seat to right side of your body. Stay low, and hold the seat very close against your body so the tire won't rub against your leg. It's easier to go in circles than it is to go straight. Then learn seat-on-side in a circle to the other direction. Switch hands! Idling seat-on-side is another trick worth learning. This can lead up to crank idling.