What is that?

I could see it happen, Liam was going to grab Galen's penis.

Galen was standing on the floor as I was changing him. Liam strolled over and his eye caught sight of the appendage. I could see the wheels turning; hmmm, what is that? Up goes the arm, open goes the fingers, Galen was oblivious, more concerned with getting back to toys. I quickly pulled up the underwear, viola, the near-exploratory moment was over.

Liam is awhile from any "private parts" discussion. How many more times will this happen before that concept sinks in?