He was supposed to be taking a nap, but instead Munchkin sat on his bed "singing." The words went something like, "da da da da da," and the melody changed pitch a little, but not to anything recognizable. It was at a bearable volume.
Then, I heard him command, "Loud!" and he repeated his song at top volume.
Then, he shouted, "Louder!" and he proceeded to do accordingly.