What Exactly is a Pig-Dog? 

Pig

-  domesticated swine
-  a person regarded as greedy, stubborn, or selfish
-  a coarse, obnoxious, or pig-like person

Dog

-  domesticated canine - informal term for man
-  a mean, worthless, or contemptuous man
-  someone who is morally apprehensible

Combined they create the worst type of man and behaviors of men...............Pig-Dogs