Doing that uphill increases the difficulty by quite a bit, you could see too that guy was tired out from not going very far. In a situation like that I usually end up doing the chop-hop, which is simply hopping forward and sticking your edge each time you land so that you don't slide backwards.
Having a softer board, with rocker and forgiving edge profile also makes it a much more forgiving maneuver. To get used to the motion, the easiest way to practice is to stand on a flat, and start rocking your board back and forth. You want to get enough momentum so that you are pressing one side, popping in the air, then landing on the other side and pressing, popping, and so forth.
Once you have this down, it's pretty much just popping the board back and forth while rotating your hips back and forth.
PowderHound and TreeNinja