Jim: you are such a dog fucker
Jim: Damit Tim will you do somthing, quit dog fucking
Tim: Im so tired and half cut, Im gona dog fuck all day
Note this definition has nothing to do with actually having sex with canines.
Guy #2: Who knows how long he'll be, he's been dogfucking all day.
Ed: Oh dude, I was dog fucking that skank so bad the film would probably be illegal if sold in the civilized world. I just dog fucked that nasty cunt.