Moon Festival

I work with a great diverse group of people. I have blogged about Bangchi before, she is originally from China and I have worked with her for more than 10 years. She was leaving work yesterday and told me that last night was the Chinese moon festival. Here's our conversation:
Bangchi: Hey tonight is the moon festival.
Ozzy: Does that mean you are going to moon people?
Bangchi: What?
Ozzy: Is that where you moon people?
Bangchi: I don't understand.
Ozzy: Google it.

Bangchi gets on the elevator to leave and about 5 minutes later I get a text, "Y r a bad boy". I knew she meant "U" not "Y".

I get the story from her this morning about how she found out.
She gets out of the elevator to leave and greets another member of the department Rodney. This is my understanding of how the conversation went.

Rodney: Hey Bangchi, great to see you.
Bangchi: Can I ask you a question, "What is a moon people?"
Rodney: What?
Bangchi: I was telling Ozzy that tonight was the moon festival and he asked if I was going to moon people.

Rodney, laughing turns his back to her and pretends to pull the back end of his pants down.

Bangchi now understands and is breaking up laughing.