Robby, the lines you quoted are from Roger Miller's "Dang Me".

In the movie "Mr. Holland's Opus", with Richard Dreyfuss, he tells his class that the tune of "Lover's Concerto" is from "Minuet in G" by...dang, I can't remember!

From memory--the vocal background in "Come Sofly":

Down down, down doo dooby, dooby down (repeated)