Hello Mr Smith
After engaging in a doppleganger maneuver on a girl during doggy style sex you do not wash the hand that was in her ass. You then procede to go to a family function with her and as soon as possible you shake her fathers hand with the unclean hand that was inside his daughters ass. Walk right up to him and say "Hello Mr Smith!"
I couldnt believe my luck when my girlfriend's asshole father ate chips and dip right after I gave him a Hello Mr Smith!