"For this dance, decide which one of you is going to be the lady and which one of you
will be the gent. Put the lady on the right.
Don't worry, it's not permanent, I promise. In another dance I'm gonna call
you "foxes" and "squirrels" -
they're just traditional calls that rhyme well - I promise no one will actually sprout
a tail or any other bodily appendage."
or
"Decide who's going to be the lady & who's going to be the gent.
Don't worry - I *know* none of you are really [gentlemen/ladies] - That implies good
manners and decorum."
or
"Decide who's going to dance the role of Lady and who's going to pretend to
be a Gent. Someone told me once I should use other non-gender-specific
words like "Aardvark" and "Duck", but I kept getting into trouble with
the rhymes.... So now I stick with Lady and Gent. Much safer."