I don't know why you expect to be different from all the other parents, we all desparately make up words.

I use ... if that Billy Goat runs away, daddy's going to get you a horse and sleigh.

If that horse and sleigh turns over daddy's going to get you a dog named Rover.

If that dog named Rover won't bark, daddy will get you a meadowlark.

then I start getting desparate.

There was a parody done by the Brothers In Law in the sixties called 'Lullaby to a Spoined Brat' does anyone have the lyrics to that?