Go ahead. Try it. According to this new study, it should work.
From Science News:
_It’s not just Frisbees and sticks. Dogs catch yawns from people, too.
Dogs watching a person yawn repeatedly will yawn themselves, says Atsushi Senju of Birkbeck, University of London. Just as that big jaw-stretch spreads contagiously from person to person, it spreads from person to dog, he and his colleagues report in an upcoming Biology Letters._