shake hands with a personal friend

During a good manners and etiquette class, the teacher says to her students:

"If you were courting a well educated young girl from a prominent family
and during a dinner for two you needed to go to the toilet, what would
you say to her?" Mike replies "Wait a minute, I'm going for a p."

The teacher says : "That would be very rude and improper on your part."
Charlie replies: "I'm sorry I need to go to the toilet, I'll be back in a minute."

The teacher says : "That's much better but to mention the word
''toilet'' during a meal, is unpleasant."

And Billy says: "My dear, please excuse me for a moment. I have to go
shake hands with a personal friend, whom, I hope, to be able to
introduce to you after dinner. " The teacher passed out..