Foot-in-mouth

To those of you who know about the Boy's epic foot-in-mouth syndrome, he had a corker today. It will go down in history and is still making me laugh out loud 4 hours and 16 minutes later.

It was a classic case of the Boy being super sweet, kind and considerate, but making a cringe-worthy mistake. How does he do it?

I'm afraid I promised I wouldn't tell, so there's no point asking. Sorry!