When an aroused man frantically rubs his turgid penis, it gives the impression that he is polishing it until it shines; hence he is a nob shiner. Used as a derogatory term to indicate a person who is behaving foolishly in the eyes of the speaker.

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life

one whom shines nobs