When a bunch of questionable dudes each take a paper plate, go upstairs, cut a hole in said plate, work one up, put their respective cocks in said holes, go back downstairs, and present before an appropriate panel of judges (panel is made up of fellow dudes, not gals).
Cockoffs can also take place in a dudes backyard....perhaps at some sort of celebratory cook-out.
Weasel: Blake......I guarantee I have a larger COCK than you.
A medical procedure by which a Gentleman who wishes to transition into a Lady, has their genitalia lopped off, whilst creating a bit of a tuck in front of their bunghole, to resemble a vagina.
The reverse of this might be called a Strapadictomy, whereby a Lady alters their genitalia to resemble a penis.
"Here, have you heard about Arthur?"
"No?"
"He's now a Martha, 'he's' has a cockoffscopy!"
"Blimey that's gotta itch."