How Do You Darkslide On A Skateboard?

When I go to the skatepark with my mates one of them (Billy) can do this really cool move caleld a Darkslide. I've tried to copy him over and over but I can't do it. It involves Kickflipping onto a grindin, slipping the board upside down and grinding with the board tape facing down if that makes sense. Now most of my other mates BMX, Rollerblade or Scooter. Only me Billy and Ollie skateboard. According to Ollie there's a certain way of doing the Kickflip onto the grinding thingy which isn't like a normal Kickflip. Can anyone walk me through the methods on how to do it please?