Easier than you think just setup for a reg 2 on, you'll have extra air so most of the time you can spot when you're about to land on the rail. This trick just floats around if you commit, you'll spin, then all of a sudden you'll be on the rail, I look down to my skis to make sure I lock on correctly. However, I can vividly remember trying my first two on to a down rail and not spotting simply spinning onto the rail, first attempt I wrecked, got up and realized I was being a pussy, second attempt I spun, looked down, landed, and rode away a thug. Not hard, just one of those tricks that seems scary if you've never done it, afterwards though you'll be able to pull them out all the time.