Running round the house with a pickle in my mouth......misbehaving
I've spent way too much time thinking about this song. There's a lyric later on that goes like this:
"Daddy won’t you listen Don’t go missing I’m behavin’"
Sounds like the first verse is stuff their drunk father used to yell at them, like
BOY, don't be runnin' in my house! And get that damn pickle out your mouth!!
Then later on he leaves his wife, the wife and kids "meet that Man in the Thorny Crown" (i.e. become "Born Again"). And then the kids write a song to say "We're behavin now! Please don't be missing! I'm eating my greens and everything!"