Great thread, not least because the Canadians and the Americans can probably unite (for a change) against the Brits/Australians.

I'd like to propose bum as a great British word, so soft and curvy and yummy. I can't understand why North Americans have a problem with it. To a British reader it sounds far better than butt or buttocks.

Just for the linguists, both words are Middle English (ie pre 14th century.)

My opinion...
Engorged manhood. NO
Knickers. OK
Suckled, Suckling. OK I guess
Globes (meaning breasts) NO!!
Twat. GOD NO!