The Backside 180
OK, you know what a 180 is, now you want to spin backside. The idea is exactly the same as a frontside 180, but you want to spin the opposite way. This is harder to learn because it is harder to get your body to spin 180 degrees in that direction and keep the board underneath you.

STEP 1: Place your back foot on the tail, just like an ollie. Place your front foot in the normal ollie position, maybe a little bit more away from your body.

STEP 2: Allright, same thing as the frontside 180, wind up your body the opposite way (to the left for regulars and to the right for goofy people). Ollie, and when you ollie unwind your body and spin backside. Guide the board with your feet, and make sure to try to keep it underneath your foot. Land in the switch or fakie position and roll away.