It ain't THAT impressive - and yeah - it usually involves a little bar waggling and some gentle clutch flaring to pull off -
I can do it too- sometimes I can make it through a whole light. I have to stand up on the pegs though. Then you keep the rear brake on and feather the clutch so you're juuust about to move. It stresses the frame and helps keep the bike upright. If you're standing on the pegs you correct either side lean with your weight while twitching the bars. Try it, you'll see what I mean. It works on a slow creep, too. Foot on the brake and feather the clutch and you can creep forward forever without dabbing a foot.
Something to practice in the city where there's a lot of lights...