I've talked about this before, but usually when we're on long road trips, my kids like to play games and have contests to keep themselves entertained. When it's cold out (like when the temperatures are in the teens), there's usually at least one competition to see who can hold their hand out the window the longest.
We took the scenic way back to Arizona last year, and passed by the Grand Canyon. When we were near the north rim, the roads were covered in snow, and the temperatures were well below freezing (17 degrees I believe). Of course my kids had the contest to see who could hold their hand out the window the longest. I can't even remember who won, but I know it wasn't me. I didn't even play that time. I was a little nervous about staying on the road.
Five minutes after the contest ended, Mr M wanted to play again. Tortellini and Togers didn't want to because their hands hadn't yet warmed up enough to give it another go. I told Mr M that he'd need to find a different game to play.
Mr M: Alright, how about we play 'Who's Most Related To Dad?'
Me (Laughing, and a little shocked): Who do you think would win that game?
Mr M: [Tortellini] and [Togers].
Me: And why do you think that?
Mr M: Because you and mom made them, and mom and someone else made me.
Me: That's right. But you know I love you very much, right?
Mr M: I know.
And just like that, the conversation I'd been dreading having with the kid since the time he was born was over. Easy peasy.