Muff in Canada refers to the female's privates. It is a term that ranks up there (pardon me) with snatch or pussy. Fanny in Canada refers to the gluteus maximus, medius and minimus (and it ranks up there--pardon me again--with tush or bum, which as I am sure you know are 'polite' terms for the ass (or arse if yer British)).

Beaver is/are one of Canada's national symbols.

The song, "Do you know the muffin man" predates the story I linked to above, D'van.