Warning: don't try to do it yourself!
They even stand up on the rear wheels.
This Japanese guy didn't go to the dentist in 10 years, combine that with poor dental hygiene (no flossing) and this is the result.
Only one, but it's no easy task.
178 beautiful and awesome GoPro videos compiled in an insane 5-minute video. From the same guy behind these videos:
Best of web videos, part 2, part 3, part 4, part 5 and part 6.