Bum Hand
Simply when your hand smells of bum. Due mainly to having too little toilet paper and being too vigorous on the wipe.
Man1: "Pleased to meet you kind sir".

Man2: (Smells Hand) "Fuck me you have obviously wiped your arse with little paper and much vigour, this has given you 'bum hand'. Can I suggest you wash your hands before serving anymore canapes".