This is an odd little song, featuring an odd little one-shot character.
"Do What I Do" I don't remember this one from when I was a kid, and to be honest, I don't really know what to make of it. How did Ernie make friends with a snake without noticing that it was a rattlesnake? Is the snake speaking English, or is Ernie a parselmouth? (Probably the former. It is Sesame Street, after all, where even inanimate objects speak English and/or Spanish.)
From Ernie's puppet design, I can tell that this sketch is from the '70s, and it really shows in the music in those last two verses about being angry.