Clunge - as made popular by the inbetweeners. Flange is 15 years out of date, surely?
Quim is a splendid word, yes, as is twunt, but this is primarily used for insult purposes.
PEDANT ALERT
In one of the Reggie Perrin series there was a mad Scottish chef who used to shout "Up yer clunge", (I think that was all he ever said) but that must have been more than 25 years ago.
I like the way the writers got round swearing/watershed issues with phrasess like "Naff off" and "you nurk" in porridge.
Anyway for non-rude wods it's PLINTH for me at the moment, the shape's nice when you say it. Bollocks is my favourite word rude or not.