If he's getting goose bumps or has purplish tone to his hands and feet, he's too cold and needs a blanket or a hat and socks. If he's flailing his arms and legs or turns from the light then he might be over-stimulated, so take him out of the current environment to a quieter one. If he's blink and yawning as well as kicking, then he might be tired. And if he's squirming and looking around, he just needs a cuddle.
Find out more about this book:YOU: Having a Baby: The Owner's Manual to a Happy and Healthy Pregnancy