dawn is for the birds (слэш)

"What are you doing?" Arthur asks, announcing his presence.
Merlin's head jerks up, startled and then he — disappears. Arthur's mouth falls open, and he stares at the empty bed. A moment later, Merlin's voice speaks, out of thin air.
"I was practicing something." And then, tentatively, "I don't quite have it yet, but I think it's working."
"You think," Arthur says, faintly.