If your dog pesters you for petting when you need to be doing something else, break off visual contact with him. You can use your torso to push him away with a body block (remember not to use your hands) or turn your head away (chin raised) in a benevolent but royal dismissal. It’s amazing how fast dogs will go away if you break off visual contact with them. It’s equally notable how hard it is for us humans to do that when we’re trying to get our dogs to do something. All of our instincts seem to have us look at our dog, just as primates do when they are trying to communicate directly with another individual in the troop. But the look that works best, that we use ourselves when we’re not thinking about it, is that slightly snobby, hard-to-get look when we turn our head away in dismissal. It works with dogs as well as with humans. Honest. Dogs can take you for granted just as anyone else in your social group can, and most of us hate being taken for granted. You might be stuck with it from some of the people you know, but you don’t have to put up with it from your dog. [The Other End of the Leash: Why We Do What We Do Around Dogs-Patricia McConnell, Ph.D. · 2009]
What's the meaning of the 'it'? here