On course we found the group approach worked best, with someone doing the "controlling" someone as "pilot" and someone else "supervising".
It makes it easier if you have one person just checking for mistakes. If everyone is role playing you can get caught up and miss errors which then become standard. If you do find a phrase that you struggle with go over it until you get it right then continue.
If you were actually controlling you would need to get the message across to the pilots and there will be times when you will make mistakes but as long as you don't let yourself get flustered you will be ok. Good luck.