Answer:
Imagine sweating on a stage, having a million and one people looking at you on a stage, and you have to present a speech to everyone carefully staring you down. And suddenly, you forget your lines!! You start sweating up and down, nervously laughing, shuffling your feet, doing anything you can to avoid this embarrassment. And the only help anyone can offer is to "imagine everyone in their underwear." That's going to make me more nervous! What helps me tremendously is to take a huge breath and tap a little beat with my fingers on my thigh and sing a little beat in my head. Then, I take myself back to all those times I practiced my lines, and what I said when I was practicing them. And automatically, it always helps me to remember!
Answer:
The central idea is that using the invisible ink was a good choice because the other side couldn't tell what it said.
