"Not exactly how it works. One day when you’re far less angry about my unwelcome intrusion in your mind, I’ll explain how it works. It’s actually incredibly complicated. I can shorten it to I wait until your REM sleep is deep enough that I can slip by your shields without waking you. I find the active part of your brain and slip in. You are still building the world that I walk into and this is where your brain put me in your dream world. Or you are incredibly calm during nightmares." If ghost Draco was breathing, which he wasn’t because he wasn’t real, she imagined he was holding his breath. Likely waiting for a snarky retort, or for her to be angry at the reminder of this ability to invade her privacy without her permission. 