Sex is communication. Sex with someone you aren't in love with, then, feels like a promise you mutter under your breath, not sure if you can keep it. It bugs you. You're in bed together, but you're not in the room together, not exactly. You're strangers to each other, even as you're sharing the kitchen table, the office cloakroom or the chandelier.

When something deeper is going on, though, it's more than just an absence of anxiety. It's a miracle of presence. You're both there in the room. You're exposed to each other, not just the night air. It combines the excitement of fresh discovery - wow, look how naked you are all of a sudden, is that for me?! - with the risk and reward of intimacy.