Twice in the last three months I've seen patients with minor dog bites and I've counseled them on how not to get bitten by their dogs. This is not trivial. Dogs play hard, and if a dog does not learn to inhibit their bite around humans, he/she could playfully bite a child. Teaching bite inhibition to dogs is critical.
(As an aside, one of the first dialysis catheters I placed as a resident was in a patient with overwhelming sepsis from Capnocytophaga canimorsus related to a playful dog bite. The patient developed kidney failure, required multiple extremity amputations, and died. This helps explain why I'm sensitive to the topic.)
An effective method of teaching bite inhibition is this: If the dog nips you, even slightly, yell OWWW! as if they just bit through your hand. Then get up and ignore them completely for five minutes, at which time normal play can resume. This quickly teaches dogs that biting humans is wrong and it demonstrates the fragility of human flesh.
More information courtesy of Clinical Cases and Images: "Prevention and Treatment of Dog Bites" and a patient handout.