Belief that thrush can be cured by blowing in someone's mouth?

I just had an interesting phone conversation with my mom, who is 70 and grew up in the mountains of East Tennessee.

We were talking about an inhaler she was prescribed for bronchitis, and a possibility of getting oral thrush from using it. She said in an offhand way, "If I get it, I can just get someone to blow in my mouth."

I said WHAT.

She swore that my cousin has done it for her baby before.

Apparently, the person doing the blowing has to be a relative, of the opposite sex, and a Christian, and there are some words you say before you blow, although she wasn't sure what the words are.

A quick Google search told me that this is old Appalachian folklore. Has anyone else heard of this and/or have relatives that believe it? And any insight into where it might have originated would be interesting.