I was on IOE with a pretty cool CA and we were about 10 mins from our destination. Ding Ding...The FA asked us if an old lady could use the restroom and without missing a beat, the CA said, " Number one or number two?" Before he could tell her he was kidding, the FA was off the phone and went to ask her. A minute later, Ding Ding..."ummm, she said number one". The CA told the FA it was ok for her to used the restroom then. We laughed all the way to the hotel.