"Fathers and Daughters (Doo-Doo in My Butt)" is a song by Chaos Chaos featuring vocals by Dan Harmon, Justin Roiland, and Ryan Elder. The song appears in the episode "The ABC's of Beth" as Beth Smith and Rick Sanchez are cloning Tommy.
Lyrics to "Fathers and Daughters (Doo-Doo in My Butt)"
I've got a doodoo in my butt
And I don't know what to do
With the doodoo in my butt
But I know that a father should say to you
That he's proud of you
Every daughter is a doodoo from a father's butt
Biologically speaking, the butt is a nut
And every father father's wrong
And there isn't a song that can change that