One's knees, as it is most common to prayer while kneeling. Sometimes written as one word. I was down on my prayer bones all night asking God for advice on what to do. Church has always been a regular fixture of this community, getting together each Sunday and getting down on our prayer bones together.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. the knees. He pushed one of his prayerbones into my gut.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.