Frank Kogan

I wonder how much this has to do with, not my in-mouth perception, but that I always brush my teeth with the same hand and that the mouth is a small enough area that the angle going into one side isn't so different from the angle going into the other. I'm righthanded, so when I'm towards the back teeth with my toothbrush, I get the feeling of being left whether I'm in the left side of my mouth or the right. I doubt that this is the entire explanation or that it's even the main explanation. But it could be a factor.