The former wife of Pulitzer Prize-winning author Cormac McCarthy was arrested on Saturday after allegedly whipping a gun out of her vagina and threatening her boyfriend.

Jennifer McCarthy, 48, got into an argument with her 53-year-old lover about space aliens, according to an affidavit obtained by news site The Smoking Gun.

McCarthy left her Santa Fe home then came back and changed into lingerie. The outfit was accessorised by a silver handgun placed in her vagina, with which she began to have "inner course", [sic] according to the affidavit.

McCarthy reportedly posed the question: "Who is crazy, you or me"? before pulling out the gun and pointing it at her boyfriend's head, the Albuquerque Journal reported.

The boyfriend told deputies that he wrested the weapon away from her and put it first in the toilet, then the trash can.

Gossip website Gawker's Tom Scocca was inspired to write a comedic take on the incident in the style of Cormac McCarthy.

"She was in the doorway. She had stripped in there and dressed her body for the boudoir, soft ladyclothes baring flesh and something more, down at the forking of her legs. Hard nickelplate steel, the Smith & Wesson. Her hand was on it. Who's crazy?"