Green’s Dictionary of Slang

(orig. US) to admit an error; thus confession n., a tutorial.

1842		Spirit of the Times (Phila.) 16 Mar. n.p.: Your honor, I confesses the corn. I was royally drunk.
1853		Paige Dow’s Sermons IV 127: He might as well have confessed the cob [DA].
1947		M.H. Boulware Jive and Sl. n.p.: Confession ... Conference with teacher.