Turn up your head shake!

We went to Utah this weekend and on the way home David and I were talking and I asked David a question. I was driving so I couldn't tell that he had answered me. I asked him, "yes or no." He said, "I shook my head yes." I said to him, "I can't hear you shake your head." Amy in the backseat says to her Dad, "Turn up your head shakes, dad!" We both started laughing. I love all the funny comments she comes up with.