"Lustig reed he" is of an old man who wanted to ride a horse but had neither horse or necessary accoutrements. He had an equally old loving wife who was prepared to improvise for the missing items by using much fantasy and normal household articles. Naturally enough, the result was very jolly.
It's a jolly tune which Bernd Gerken in the Idle Fellows sang so well and I much enjoyed belting out the chorus "Lustig reed he, ja, lustig reed he".