Cups Runneth Over

Baseball is in full swing with our first game last night. The boys played a great game despite the handicap of running with a block of plastic in their pants. Yup, the boys are all grown up and getting used to wearing their cups. Is there etiquette where cups come in? Is "knocking" on the cup considered rude, crude, or socially unacceptable? Is there cleaning involved? If so, who is responsible for the cup's hygiene? I'm not touching that thing, I draw the line!