How Exactly Should I Take This?

I was laying down with James this afternoon to help him settle down for a nap. We were just quietly chatting when the following conversation took place:

James: Mom, I am getting to be SO big, aren't I?

Me: Yep. You really are a big boy.

James: I know. But I'm not as big as you. You are REALLY big!

Me: Uh huh. (hoping the conversation ends here)

James: You are big. But some things are even bigger than you. Like whales.

Thanks, son! Remind me to have your dad talk with you about what NOT to say to a woman!