Poll Results

Total votes: 2323

Upper left, outside surface: 757 (32.6%)
Somewhere different each time: 392 (16.9%)
Upper right, outside surface: 263 (11.3%)
Lower left, biting surface: 225 (9.7%)
Lower left, outside surface: 184 (7.9%)
Lower right, biting surface: 107 (4.6%)
I don't brush my teeth: 98 (4.2%)
Lower right, outside surface: 74 (3.2%)
Upper left, biting surface: 63 (2.7%)
I don't have teeth: 43 (1.9%)
Lower left, inside surface: 36 (1.5%)
Upper right, biting surface: 33 (1.4%)
Lower right, inside surface: 21 (0.9%)
Upper left, inside surface: 17 (0.7%)
Upper right, inside surface: 10 (0.4%)

Yeah, I forgot the "in the middle" options. I meant to put those in, really, but they slipped my mind when I was typing.

And thanks to those people who wrote in to say "in front of the bathroom sink".