If you still refer to your friends as your "dog" you need to stop.  Firstly the age of DMX is over, I know, I know, "Ruff Ryders for life" was the quote but as Ed Lover would say "C'mon son" we aren't living in the 90s move on with your life.  Next, calling someone your dog basically means you are calling them a toilet drinker(see above^).  We are living in a global economy you can't go around calling people "dog".  You could call someone your dog from another culture and they might get highly offended.  Beware of the dog, I mean be aware of the word dog.