1. rubbing
He stood by the gate, rubbing his hands together.
Now that you mention it. Yeek, Hideki's habits are rubbing off on me!
What police thought was a distressed cat turned out to be a man practicing the cuica, a drum which produces noise by rubbing a stick attached to the drumhead from the inside.
2. grinding
I find that I get the best flavor by grinding fresh peppercorns.
This decision was accepted with grinding teeth.