We don't need to find them - you can use it to imitate someone who's not around right now. And it can be me, if you want, it'll still work - it's just that it should be someone who has fairly distinctive body language and nonverbal communication. That way we'll know for sure whether or not it's working.

And it would probably be easier if it's someone you know pretty well, too. Can you think of someone like that? [It's up to her if she thinks his body language is distinctive, or if she feels close to him - he's not sure he can properly be the judge of either of those.]