December in a public school was always kind of a crazy month with students anticipating Christmas Break. I taught students Christmas carols because it was a very controlled activity. It was also easy to teach the words of the song through pictures. For example, I taught my students the song Fum, Fum, Fum.
I would use pictures and arrows to explain the words of the song.
A week or two before Christmas break, I would send out an email asking all the teachers if my students and I could come sing Christmas carols to them (knowing that they would have an audience made students put more effort into their preparation.) I would also ask teachers if they preferred if we came at the beginning, middle or the end of their class. I would then make a list and plan our caroling route accordingly.
Some students were really shy about it, but others embraced the experience, and there was room for both in this situation. During the caroling, I took photos. I then showed these photos to my students when they got back from Christmas Break. I felt like it was a fun way to remind them that school could be fun.