start with a leg on either side, then pop up and bring your legs together and stop at 90. do it like your doing a slowish wide stance 360, but only spin 90. just like a ride on box, but its skinnier and upwards. make sure your weight is centered or else your slide to either side and usually if the drop is high enough it can hurt. make sure you can do pipe style rails before doing this. or just fuck it and huck it. also, SPEED IS YOUR FRIEND. you can almost never be going too fast for a cannon