The act of a man masturbating himself to climax in a urinal in a club, usually because his date has ditched him and it is slim pickings for sloppy seconds.
'So she hooked up with somebody else then? What did you do?
'Well everyone else out looked like Russianfemale weightlifters so I just has a frosty john in the toilets.'
'At least you got a happy ending then bro.'
Doing strange or foolish things in real life in order to dilute search terms for something you want to bury online.
Boris Johnson was out there frosty johnsoning again -- talking about how he likes to paint red buses. It's even more blatant than that Warner Brothers announcing a fake live-action Frosty the Snowman movie to distract from workplace harassment allegations.