This is Why Your Dog Sneezes When He is Playing Hard
My dog always sneezes on me when I play rough with her and it used to gross me out a little. I mean, who wants doggy snot all over their hands and face? But after learning why they do it, I love her even more.
Why would a dog need to sneeze during a bout of fun and excitement? According to dog behavior experts, the sneeze is not because of allergies or an itchy nose. It is a signal to other playmates that they're just playing. The sneeze tells us and other dogs that this is just play and helps keep it from escalating into a real fight.
You can also tell that your dog wants to play and not fight if he bows (front end down, rear end up). It is a friendly gesture that invites another dog - or human - to play.