Sidewinder

Vashek Kroutil teaches you the Sidewinder trick in this video. You do this short but extremely important trick by throwing a Sleeper and then jerking your hand up so that the yoyo starts winding towards your hand, but at the same time jerking your hand to one side or the other. If you do everything correctly, the string around the yoyo should unwind, just like in the video.

This trick is for beginners, but most advanced yoyoers use it to "unwind" the string in all possible ways (e.g. in combination with a bind).