Children's Book Magical Boy w/ Catchphrase "Ding Bog Fartham Still"

[Mary]

Request from a library patron for the following. I'm sorry I don't have more details.

I'm looking for a children's book that is about a boy with magic. I can't remember the title or author but the boy repeats his magic words "Ding bog fartham still". Is this phrase enough to jog a librarian's memory for the name of this book? It was funny and my kids loved it. Thanks.

[Rainbowheart]

A Special Trick

To reverse all spells one at a time, shout as loudly as you can: Ding bog farthum still. And if that doesn't work, shout it backward: Still farthum bog ding.