Washington's Second Rule of Civility:
2d When in Company, put not your Hands to any Part of the Body, not usualy Discovered.
Modern interpretation by two 10-year-olds and a 6-year-old:
Don't touch your privates or do anything gross with your body like pick your nose. You shouldn't touch parts of your body which are covered by clothes when you're in public - pick your toes, scratch stuff, things like that.