You should know how to B/S 5-0 Grind before trying this trick.
Come up to your target at a nice speed and almost no angle. Pop and ollie and drag like normal, make sure you get quite high above your target. When your around your top height and just before you start coming down stretch out your back foot and twist your shoulders 90 degrees. This should force your whole body to get your tail onto the board. Another thing you have to do in the air when you are spinning, you have to put all your weight on your back foot to make sure you stay on a tail slide for your whole target. You will have to find out how much to lean yourself, it depends on how fast the target slides. Keep trying this until you can finally stick on for a nice amount of time then start trying to get out. Just a simple turn and shifting your weight evenly over the board will get you a landing. Just remember when you ollie shoulders are with the board, when your in the air you twist the board and your shoulders 90 degrees, board and shoulders still inline. Shift your weight to back foot. Test your slickness of target couple times, then try to land.