It does that automatically on the benches that are similar to those but with a thinner rail.
I think I tried doing this a few times but couldn't get it down.
Yeah, I had to press Y (or Triangle on PS3, I assume) as soon as I hit the rail to catch the board again. I was actually able to recreate this a few times, it's not too bad.
I've watched this 5 or 6 times and still have no idea what the hell happened, looks like you did a hippy jump and somehow managed to step off the rail?