I may regret asking, but a couple of times recently, I've passed riders going in the other direction, and they wave enthusiastically and rap on the top of their helmets like they're knocking on a door.
What, if anything, does this mean, the rapping, that is?
This is in the SF Bay region.
What, if anything, does this mean, the rapping, that is?
This is in the SF Bay region.
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