I've heard this song sung by Bill Hinkley & Judy Larson, who were once frequent guests on "A Prairie Home Companion." They would ask the kids in the audience to shout out names of colors, for which they would then "improvise" a rhyme. (I suspect they've performed this song often enough to be prepared for anything, but for entertainment's sake, you've got to pretend it's difficult.)

I remember their rhyme for orange:

"I won't wear orange; it's the color of a door-hinge" – a rusty one, I suppose.