I came across this phrase when I was reading a detective novel An Innocent Client by Scott Pratt.
A policeman found the dead body of a priest with his penis cut off and said this to himself.
"What'd you do to get yourself killed, Rev?" Lander said to the photo as he turned into the parking lot at the Purple Pig. "Dip the old wick in a vat of bad wax?"
I'm not Christian. And that makes it even confusing.
Thank you so much.
Nothing to do with being a Christian (except that vicars are supposed to be morally good)
The policeman is suggesting (euphemistically) that there is a sexual motive for the murder.
"Dipping one's wick" is a common euphemism for having sex, but it literally refers to the process of making candles by repeatedly dipping string (a wick) in hot wax. The policeman extends the common metaphor. He is wondering if the vicar has "dipped his wick" in "bad wax", ie had sex with a bad person, and as a result of this has been murdered, perhaps by the girl he had sex with, perhaps by the girl's boyfriend or pimp.
