I wish I could have heard your dad sing it, Acme. Do you have any recordings of him singing anything? Did he ever do studio recordings?

And Lomax:

MY SWEETHEART'S A MULE

My sweetheart's a mule in the mines
I drive her without any lines;
On the bumpers I sit
And tobacco I spit
All over my sweetheart's behind.

Source The Folk Songs of North America (Alan Lomax, 1960), page 131

reprinted from Minstrels of the Mine Patch, by G.G. Korson (Grafton Press, 1927)

Notes from Lomax:
65. MY SWEETHEART'S A MULE
MINING MULES were almost as tough as the miners themselves. Horses usually proved too nervous for underground work, but a mining mule, with a leather guard to protect his head from the roof, and a flickering lamp set between his ears, could surefootedly pick his way along the dark passages, pulling several times his own weight in coal. A mule became so accustomed to life underground that, when he was put out to pasture in the sunlight, he would refuse to eat grass until he had watched his companions for several days. Despite their stubbornness, they proved to be tough, unexcitable, loyal members of the underground team. The men grew deeply attached to their four-footed comrades, and sometimes went on strike when the management transferred a mule from one mine to another.

---

B.A. Botkin's A Treasury of American Folklore (poage 864-865) has the Korson version, along with what Botkin calls a "bowdlerized" version that I posted from the Silver Burdett school songbook. Botkin says the air is "My Sweetheart's the Man in the Moon."