Example usage:
"Jim, that shipment was supposed to go out thirty minutes ago, quit fucking the dog!"
or
"Hey what are you up to right now?"
"Oh, nothing, just fucking the dog."
or
"Isabelle hardly gets anything done, she's a real dog fucker."
or
"My manager at work just fucks the dog all day, I have never seen him do anything useful."
I'm Canadian but I use it from time to time. I also say "seducing Rover" or "making puppies" when I'm in mixed company.