In online multiplayer mode, find a shopping cart. Make sure you have someone with you. In multiplayer mode, everyone has their own shopping cart. In other words, that the shopping cart on your screen is invisible to everybody else. Run into the shopping cart and make sure it moves. While it is moving, try jumping on it. If done correctly, your character will appear as if he is drunk and stumble everywhere, but on your friend's screen it will appear as if you are sliding on the ground. Sometimes you will slide/stumble longer than others. You can do this in Story mode, but you will only stumble.