When my kids were little, I would use a magic marker to draw a happy face on their hand when they did something good!
The happy face is a reward but it’s not a candy or something tangible. We want them to feel inherently happy they listened. The drawing is more like a reinforcement of the behaviour, they look at it, feel good because it reminds them they are good inside and it made mom/dad happy!
Was reading Daniel Siegel’s book “No Drama Discipline,” I was struck by his second point under his REDIRECT model — this is to “embrace emotions”. So, say yes to desires and no to behaviours, & redirect to appropriate actions.
So if your preschooler is visiting you in the night, say: “I know you like seeing mom in the middle of the night, we have a special bond that no one can break. But, coming to my room stops my sleep and makes me too tired to take you to the library. Next time you want me, hug your teddy instead and remember you’ll see me in the morning. Won’t it be nice to have breakfast in the morning together after we’ve had a good sleep?”