Me (yelling): "Did you show anyone your underwear today?"
Me: "Did you show anyone your underwear today?"
Repeat two more times...
When he finally understood he was silent for a moment and then he said "no". Since he's only seven he didn't say anything like, "Are you insane? What kind of question is that anyway?". Instead he probably just thinks it's a question that your Mom or Dad will occasionally ask you. It's actually a good idea. You can never remind your kid too much NOT to show others their underwear. Really, you can't stress this enough.