Um...Hum?

The boys are in the middle of their swimming lessons and are really enjoying them. After Dallin's class last week, his teacher came up to me and said, "Dallin told me he doesn't know how to hum." And she said it in such a way that it seemed like she couldn't believe we hadn't taught him this! I felt like I had to make excuses, "Uh, I guess not. I usually just sing and Steve whistles a lot, but we don't really hum. Sorry." She went on to explain that's how they teach this age group to keep the water out of their noses. She asked me to teach him and practice with him. Okay, I can do that, or so I thought...
That afternoon I tried to teach him, telling him it was like singing but with you mouth closed. Well, he said he couldn't do it and Caden needed to teach him. I have no idea where he got the idea that Caden needed to teach him, but Dallin is very stubborn and once he gets an idea it stays there. I kept trying to get him to try, but he was freaking out saying he needed Caden, so I dropped it.
After school, as the boys were playing, I heard Dallin say to Caden, "You need to teach me how to say 'Um!'" It was really hard not to laugh at him, because he was trying so hard to communicate it to Caden. I told Caden what he meant, and Dallin copied him perfectly. He is such a stubborn, funny boy!