It was a quick tap just as B came to an edge, to cause him to fall off the edge. It made many shortcuts possible. But that move is almost impossible to do now, since the game has been updated. So it is no longer a problem and older levels that used it intentionally are considered unwinnable.
How about this one? What is it name? Is it hated move too? (Only want make sure before using this) Here is the card:
@BLR That's a kind of inertia move. You can try it and see. If players have to go back and forth many times like in your video, I think most people will not like it very much.
