What is what to say when someone says you have a nice bum?

When someone compliments you by saying you have a nice bum, you can respond in a way that balances politeness and comfort based on the context and your personal feelings. Here are a few suggestions:

1. Thank You: A simple "Thank you" acknowledges the compliment graciously if you're comfortable with it.

2. Humorous Response: If you want to keep the mood light, you could say something playful like, "Thanks, I’ve been working on my squats!"

3. Set Boundaries: If the comment makes you uncomfortable, it's perfectly okay to set boundaries. You might say, "I appreciate the compliment, but I’d prefer if we keep things professional/appropriate."

4. Redirect: You can steer the conversation to a different topic by saying, "Thanks, how's everything going with you?"

5. Ignore: In some situations, especially if the comment feels inappropriate, it might be best to ignore it and not engage further.

Always prioritize your comfort and the context of the situation when deciding how to respond.