Instead of being an extra verse tacked onto the end, though, this is a substitute for the original last verse:
He missed his little friend
And brooded for a while,
Until another little boy
Showed up to make him smile.
When taken out of context
This verse sounds really wrong,
But it's all innocent, I swear,
It's a family-friendly song!
If I were a folksinger performing this in concert, I think I'd end with a spoken comment along the lines of: "That's right, there are no hidden double meanings in this song. If you disagree... what have you been smoking?!"