I know it works with people. I do it to Buddy all the time. But Buddy is strange in many ways, so I figured it was just him. I tried it on Choco all week and it worked every time.
Guess I'm showing my boring life here, aren't I? :-\
If I yawn, Zoe doesn't yawn.
What makes her yawn is when I scratch the side of her face.
Linda and Zoë, the Umlaut
When Puff is looking at me and I yawn, 75% of the time she'll yawn, too.
Puff [YF, AKC field line (from competing HT/FT breeder) 62 lbs, dob: 8-'01]
Bess [BF, AKC bench line (from competing show breeder) 55 lbs., 1967-1981] "Poor Bess, the Wonder Dog":
Fudge has a yawn "spot". If you rub very lightly between his shoulders he will let out a big yawn.