However you prefer! There's no right way.
Let's take this sample question:
"If you could freeze time with Luke, what moment would you stop on?"
Here's an example of how you might answer this question in third person:
Any time that Luke is snuggling in my lap. I could be happy in that moment for a lifetime.
If you prefer, you can write directly to your child:
Any time you are snuggling in my lap. I'd be happy with you right there for the rest of my life.