Not that rare, apparently. Some people deliberately sting their penises to make them swell up more.
Bee-rotica: A beginners guide to insect sting fetishes
Hookworms, bee stings, and other forms of autoimmune hormesis promise to be effective treatments for our many autoimmune diseases of affluence.
I'm guessing she's just treating her arthritis, as she indicated, and they paid her some cash to call it an addiction.
Fapping to tranny porn all of a sudden seems super normal.