I LOVE this lesson. It's the one I always look forward to doing because it's always sooo unexpected but MOST appreciated. If there's one truth I've found in my years of teaching, kids love these by-the-way lessons--it's like a heart to heart. For my high schoolers, they seem to say, "Finally, someone's treating us like adults!" (You know they get really tired of people calling them CUTE because of their beginner-level language....)
At the beginning of the episode, I left it up to the listener to pick and choose the information for their populations' age/background/etc. But I thought it would be helpful here to expand more upon what I personally choose to tell. I omit the bit about not bribing police officers to high schoolers, but I do mention it to my college-aged students. Regardless of age, I mention the frequency of use of showers and deodorant. I've never had a student be offended at being enlightened on that point.
I did have a friend (an American) in college that had not been brought up using deodorant or showering with enough frequency, especially in hotter weather. She was teased behind her back mercilessly and people didn't treat her well. I felt it was a most ungracious justice seeing as she was hilarious and always kind to everyone. Finally, I approached her about it as kindly as I could and it turned out she was so grateful for a chance to discuss it, as she didn't understand where she was going wrong. It turned out she needed to change the brand of soap she was using and use a little more shampoo than she had been. Problem solved! I think a lot of times people choose to avoid their own discomfort rather than to help someone solve a problem to which they don't know the solution.
I once saw an asian student's bare bum as she squatted in her stall in the bathroom, as she was on break and was probably looking at her phone after she had used the facilities. I was in the next stall over and knew who it was since my class was the only one on break. This is obviously not something I would mention as a "heads-up" tip to the class, but it proves my point of the need of these types of lessons.
These "off-the-books" lessons are so important as many of our students gain whatever knowledge they can of American culture from movies and then arrive, hoping to fit in.
I'd love to hear what tips you give your students!