Start at the top of the wave. Place your paddle in a rudder position behind the back of your boat. You are going to rotate around the paddle. When you first start to spin around your paddle you're going to have to remember that this is a flat spin. KEEP YOUR BOAT FLAT. Keep your weight centered over your butt. It is very common to see people trying to use their edges to spin. By dropping an edge while your trying to spin, the current will grab it and pull you off the wave and probably flip you in the process.
Start the spin with a small pry with your back rudder while dropping enough weight into the upstream edge to match the angle of the wave, which will help the boat break free and start to slide. With a flat-bottomed boat you should be able to surf as well sideways (called a grind) as you do frontwards or backwards.
When you start your spin turn your head to see where your going. Use your pry to finish spinning you into a back surf. Now just relax and enjoy the back surf for a moment. Your just got a 180 flat spin!
Second 180 - The second 180 spin relies on the same principals as the first 180, but here many people have a tendency to drop an edge to finish it around. DonŐt give in. You still have to keep your boat flat.
Put your paddle into the wave near the top next to the front of your boat. Once again pry with this rudder stroke. Keep your head turned and looking now towards the trough of the wave.
On the second 180, remember to drop just enough weight to get the boat flat on the wave still. It will be on the opposite side than the first spin. After you come completely around you have done it.
