Aziraphale started awake.
Before Crowley had moved in, he'd hardly slept at all. Neither of them needed to, of course, but Crowley enjoyed it so much that Aziraphale hadn't been able to resist the demon's temptations for him to join in. Before he knew it, he found himself ending most days intertwined contentedly with Crowley, dropping off to sleep to the sound of his soft breathing. So, waking up was a sensation Aziraphale was still getting used to, and it took a moment for the angel to orient himself, and realize why he had woken up so suddenly.
On the other side of the bed, Crowley was moving in his sleep, and a sore spot on Aziraphale's shin suggested that he had just been kicked. Blinking himself a bit more awake, Aziraphale pushed himself up on one arm and rubbed his face. As his eyes adjusted to the pale semi-light of the moon creeping in around their curtains, he realized that Crowley was whimpering, writhing and shaking beneath the covers.
"Hey!" Aziraphale called softly, reaching out to place his hand on Crowley's shoulder. The demon jerked, lashing out wildly with an elbow, and Aziraphale tucked his arm back. Crowley was still asleep, but something had hold of him, and he could neither wake nor free himself from it. Aziraphale chewed his lip. Crowley had mentioned that he had nightmares sometimes but, typical of himself, had not gone into detail. Clearly, he hadn't wanted to worry, but what good was that now?
"Hey," Aziraphale said, yet more softly, and lowered himself back to the mattress. He inched his body closer to Crowley's bit by bit, until again he reached out, this time, slowly and gently placing his hand on Crowley's back. "Hey," he whispered as Crowley trembled beneath his fingers, and slid his hand over Crowley's ribs until his arm wrapped around the sweat-chill chest, and his chest pressed into Crowley's back.
"Shh… shh, don't worry," Aziraphale murmured, closing his eyes against the fearful sounds still escaping from the being beside him, "I've got you. I've got you." Still sleeping, Crowley drew a deeper breath, and shifted. Aziraphale sighed as his demon turned into him, sneaking his free arm under Crowley's neck as he adjusted position. Crowley's upper arm in turn threw itself over Aziraphale's shoulder, the other curling up between them as his face tucked itself into the angel's shoulder. Aziraphale pulled his grip gently tighter, drawing Crowley snugly to his chest. His fingers found their way into Crowley's hair and stroked methodically as the demon slowly quietened, released from his dreams in his angel's safe embrace.
"Don't worry, my love. I've got you."