I have a female tortie of unknown age - somewhere between 12 and 16. Overall she's a very healthy and content creature, but in the past few years she's developed a very strange mannerism.

Whenever she rubs against something with a corner, and the corner rubs a spot in her right cheek, she sneezes. I've been observing this for a while - it's only on the right side of her face, and only when a corner hits it. It's very consistent too - sometimes she'll sit and rub for a few minutes, and sneeze a couple dozen times in a row. The sneezes are very light, almost more like huffs - like ticking your nose with a feather. She doesn't recoil at all, and the constant sneezing doesn't seem to bother or exhaust her; she'll stop rubbing and continue on her merry way.

As mentioned, it's been happening for a few years now. It doesn't seem to pose any kind of problem to her heath, so I'm not worried - mostly just entertained and curious. Has anyone seen this before, or know anything about it? I've checked her for gum inflammation, or any kind of irritation/injuries/scars around the spot, but she's pristine. I can't even make her sneeze by scratching her cheek or poking the spot, only happens when she's rubbing.