1. A superlative act of sexual intecourse in which the mind and all the senses are as thoroughly engaged as the sexual organs. So called as the brain is considered north while the gentials are south (Mexico or Brazil); also refers to the fact that the beaver (Castor canadensisis) is the Great White North's national animal, and thus, "Canadian beaver" refers to tip-top or top-drawer fucking.
2. A girl or woman living in the country of Canada, most of which lies north of the 48 continguous United States.
I was up in Montreal gambling and I rassled me up some Canadian beaver!