Can you guess what two tricks you should learn before trying this? Yup, kickflips and backside tailslides. Approach the obstacle just like you were going to do a backside tailslide. Your front foot should be in the same position as for a b/s tailslide, only a little more towards your heel edge so you can get a nice flip. Snap your ollie and do a kickflip while turning your hips backside. In the same motion that you catch the flip with your back foot, you should be planting that back foot over the edge of the obstacle. Once you're on there, keep your hips 90 degrees to the object and your torso parallel with it. Slide as long as possible and drop off as you shift your hips back to forward. Now do it again.