This is a very hard trick to learn but it looks pretty cool. You have to know how to F/S Crooked Grind and the works.
Go at a Farley good speed and come at a 45-degree angle towards your target. Pop an Ollie and in the air twist a 180. While your twisting keep a good eye on the place you plan to land. If you don't what will happen is you won't catch the edge of your target and then you will slip out and that give you a good chance of slamming your face into the ground. If your having problems landing on it try to do a F/S Nose Grind but when you land twist you board overtop of your target. After you get pretty good at landing on the grind you have to learn to stay on the grind. While you are grind you should push forward with you front foot and lean back a little but not enough to slip out. When you can do that the easiest way to get out is just to twist your body like a B/S 180 and spot your landing. After you can do that go ahead and make up your own twisted ways of getting out.