How do we sleep when our heads are burning?

The story:

I first heard the song when I was six and clearly heard 'heads' instead of 'beds'. One day, my dad and I were driving in his car and I started singing along to the radio. I was about twelve. He started laughing, saying that it was 'beds'. I was convinced that it was 'heads' because I couldn't imagine sleeping if my head was on fire. Oh well, heads sounds funnier than beds anyway.