The typical homosexual way of saying vagina, no one straight uses this. Seriously, when's the last time you heard someone say "I'm going to take the clunge"? Or "I'm going to plunge the hell out of that clunge?"
It sounds more like some sort of product you'd see at 1 in the morning than something you'd use an awkward sexual advance.
tl;dr a typical British word for vagina
British Male: Cheerio doll, how would you like to show off that clunge there yes indeed?
British Male: *sips tea* Your cooter there
British Male: Bloody hell for the love of Freddie Mercury and the Queen, your vagina!!!