You could make the sneeze as unpredictable as possible, with some warning signs that the dragon is close to sneezing and add objects which soothe the dragon before it's too late. And if he sneezes - the player is burned for example (or if he sneezes strongly enough to trigger flame breath, if he sneezes a little - no fire yet, just smoke). Also you could make it like that - the more times and stronger the dragon sneezes - the closer he is to fiery eruption (more smoke comes out, then sparks, then even more darker smoke, then finally fire and game over for player)! That'd make this game so much more enjoyable for me. I love the idea of playing with dragons and teasing them like that.