A mule named Henry

Rock rides a mule named Henry through the swamp and is warned not to touch the mule's tail, so he says "Henry's tail will remain inviolate." Here's the point: In 1965 to 1966, Rock was then breaking up with his longtime agent, live in lover, and legendary gay casting couch owner Henry Willson, which hurt Rock's career in mid stride. Why name the mule Henry, and why discuss Henry's tail's inviolability? Rock was fond of slipping gay in-jokes into his scripts...Just sayin'.