This trick was one of the first I taught to Miki.
In this trick you hide one kibble in either of your hands behind your back, while your dog sits in front of you waiting. Then the dog needs to sniff and guess in which hand the kibble is. Miki points the hand with his paw. If the dog knows the right answer he gets the kibble. If he guesses wrong, put your hands behind your back again and start the game over. And remember to change hands frequently.
So the whole point of this is that when you get your dog to sniff and guess 50 to 100 times he will get tired. Especially when the elusive treat can disappear with the wrong guess, the dog wants to get it right at once.