While putting Z to bed, I did a relaxation exercise to help him with his fears. This is the transcript:
Me: "You're feeling very relaxed. Your feet feel relaxed. They feel heavy; even your toes feel heavy."
Zach: "I'm heavy?"
Me: "No, buddy. It's just a way to feel more relaxed. Like you're so relaxed you can't even move your body. Okay, your legs are relaxed and heavy...so heavy that they're sinking into the bed."
Zach: "Wait--my legs are sinking into the bed?!"
Me: "They're not really sinking, Zach. It's just a metaphor. You're relaxed, okay?"
He fell asleep before I got to his head, so I guess it worked for him, even with the quicksand metaphors.