Lead me guide me walk beside me

Sam and I have lived at Wymount for 2.5 months and we are moving in 4-5 weeks so imagine my surprise when the 2nd counselor came to meet with Sam and I to give me the calling of primary music leader. Now when the calling was first extended I was shocked and less than excited. Not because I wanted a different calling or anything like that, but as you probably know, I have no musical talent. It's also so new to me to be in a ward that even has a primary because singles wards do not have them for obvious reason. I wondered if I'd feel disconnected from my peers, or if people would assume I'd gone less active. But after a little more thought and prayer, I felt great about the calling and excited to learn how to be successful in this position.
Today was my first day in primary. I was only observing, as the prior music leader, Whitney, had already prepared her lesson plan. Walking in I quickly noticed that there were 6 primary leaders, and just one child. His name is Gordon and he is darling. One of the other leaders, Sister King, has a 3 year old daughter, Rachel King, so she decided Rachel could start primary a little early and then we had one visitor who was about 4 years old. So we had a class of 3 children and about 6 leaders (7 if you include Sam who came with me for moral support).
As we started to sing, I was really impressed with how well the kids knew the songs and how well behaved the children were. We started to sing "Called to Serve". Whitney stared by rehearsing the first line of the song for the children, "Called to serve him heavenly KING of glory..." As soon as Rachel King heard the word "King" she gave the funniest sounding snicker as if to say, "oh you're using my last name now are you?" so Whitney replied, "Oh that's right, whose last name is King?" and the visitor, Clark, yelled out "JESUS!"
Throughout music time one of the leaders sits in front holding something that looks like a thermometer. If the children are reverent the temperature increases, if they are being a little rambunctious the temperature decreases. Now the thermometer doesn't earn the kids a treat or a sticker but for some reason they respect the thermometer. Clark especially respected the thermometer. If Gordon and Rachel were acting up he would get the most panicked look on his face, he would put his hands on his face and start to shake his head no vigorously. It was too cute.
I love these little kids, and I and so excited about my new calling! If you have any advice about teaching children lyrics I'd love to hear it.