As I am fundamentally an evil, sadistic person who likes to make dogs (and people) suffer <Grin!>, I'll describe the mechanics of the lesson. At the end of the lesson will be some questions; once you've done the lesson, see if you can answer the questions!
I call it Doggie Zen: to get the treat, you must give up the treat.
Get out a treat that is good and smelly. Cheese works well for this, as does liver or Rollover-type stuff. Fix a few pieces that are small enough for you to cover in your closed hand.
Let your dog see that you have a goodie in your hand, then close your hand over the goodie and let the dog sniff, lick, nibble, etc, trying to get the goodie. Eventually, the dog will give up. When the dog turns their head away from the goodie or steps back away from it, even if it's just a temporary thing, catch that moment with the clicker and open your hand.
It's important to leave your hand down at the dog's level, perfectly accessible to them. Let them have a good chance to try to get the treat out of your hand on their own. If the dog gets too enthusiastic and is actually hurting you, say OUCH!, glare at them and pull your hand up out of their reach for a few seconds.
Give the dog as many trials in as many different places as you can.
Questions for Lesson 3
Why do you have to leave your hand within the dog's reach? Why not just pull it up and away from the dog until they sit or do some other behavior?
What can the *handler* learn about training a dog from this exercise?
Re-state the Doggie Zen phrase to describe training in general.