A/N So this is the companion story to the poem 'Go the F**k to Sleep' (chapter 3) Cas is having a hard time navigating his new human existence, and Dean is there to help... sort of. I really hope you enjoy!

It was 3 a.m. when Dean's hand slipped from underneath his chin, jerking him awake at the library table. He rubbed a hand over his face, letting out a long sigh of exhaustion and looking down at the piles of books that surrounded him. He had been sitting there for hours, barely moving from the hard wooden chair, waiting for a call from an old friend of Bobby's who had been trying to gank a witch in Nebraska for just over a week. The hunter had been calling Dean periodically to ask him to research the lore, but so far they had found nothing of any use. He had promised to call back at two thirty with an update, but when Dean checked his cell phone, there were no calls, no messages. He felt the beginnings of concern pricking at his insides, but he was distracted when the thick silence was broken by the sound of footsteps and the scrape of a chair coming from down the corridor. He stood up, feeling the satisfying pop of several of his stiff joints, and went to knock on Cas's door. Dean pushed open the heavy door to find Cas standing in the middle of the floor, every surface covered in half-empty mugs of coffee.

"Cas it's three in the morning," Dean said, his eyes squinting in protest against the brightness of Cas's room.

"I know that."

"Why aren't you in bed?"

"I can't sleep," he said.

"How much coffee have you had?"

"I'm not sure," he said, looking down at the empty pot on his desk and the discarded mugs. "Six cups. Maybe seven." Dean was a little concerned as he looked at his friend, who had been human for less than a week, and by the looks of things, wasn't coping very well. His blue eyes were wide, flitting restlessly around his bedroom, but the dark streaks on his pale skin betrayed his exhaustion. Before he could say anything else, a glint of light caught Dean's eye and he looked to Cas's trash can which was overflowing with empty soda cans.

"Is that Red Bull?" Dean asked.

"The man on the television said it would give me wings."

"Okay, no more late-night T.V. for you," Dean muttered, taking Cas by the arm and sitting him down on the bed. "Now I could be wrong, but I think all of this coffee and Red Bull is the reason you can't sleep."

"I'm not awake because of the caffeine, I'm drinking it because I don't want to sleep."

"Why not?" Dean asked. Cas frowned down at his white socks.

"I don't like it," he said, fidgeting where he sat.

"You don't like sleeping?" Dean asked.


"Why not?"

"When I was an angel I was aware of everything that was going on around me, every second of the day. Now I can't hear anything on angel radio, I can barely hear what people are saying fifteen feet away from me, and when I sleep, I can't see or hear anything at all."

"And you feel vulnerable," Dean concluded. Cas nodded. "C'mon Cas, you know you're safe here."

"I know that, but I still don't want to sleep. It feels unnatural." Dean looked as Cas sitting hunched on the bed, a deep frown on his forehead, refusing to go to sleep, and he found himself struggling to keep the smile from his face. "What?" Cas demanded, irritably.

"I'm sorry, it's just you look so much like Sammy when he was a kid," Dean said, pressing his lips tightly together in order to keep a straight face, but Cas wasn't fooled.

"Dean please stop laughing," he said. "You have to understand that everything is new to me right now. I'm trying my best, but I can't tell the difference between something that is completely normal and something that might kill me. How do I know if I'm experiencing indigestion or a heart attack? How do I know if I just have a headache or something much worse? I have no frame of reference because I haven't spent the last 30 years of my life learning about this. It's all new so just give me a minute to navigate all these new feelings."

"Okay," Dean said, his smile well and truly gone now. "You know, if you're not sure about something, you can always ask me."

"Thank you," he said, although he still sounded a little sullen. "Trying to understand emotions is very taxing." Dean was about to get up and leave Cas in peace when a thought crossed his mind.

"But you had emotions when you were an angel, right? Surely they're the same now."

"I experienced emotions as an angel, but they were muted and somewhat limited. Obviously I could experience the basics: anger, sadness, happiness, but the more intricate emotions I didn't understand because I just didn't feel them."

"And now?"

"Well, now I can feel them but I still don't understand them."

"Then explain them to me," Dean said. Cas looked unsure for a moment, but he eventually gave a sigh of resignation.

"Ever since I became human there's been this constant weight on my chest, and I feel like someone has my stomach clenched in their fist."

"Oh boy, I know that one well," Dean said.

"What is it?" Cas asked, looking concerned.

"Nerves, or stress. You're probably just worried about everything that's going on right now. Being human, feeling vulnerable and scared, it takes its toll."

"That seems plausible," he said, nodding.

"And the six cans of Red Bull won't be doing you any favours either." Just then there was a soft knock at the door and they both looked round to see Sam standing in the doorway looking sleepy but curious.

"Everything okay?" he asked.

"Yeah," Dean said, but before he could say anymore, his phone began to ring. It was Bobby's friend. "Crap, I have to take this," he said. "Sammy, would you take over here?" he asked before hurrying from the room towards the library, answering the call as he went.

Sam took Dean's spot on the bed. "What am I taking over?" he asked.

"I was explaining some of my emotions to Dean, the ones I don't fully understand since becoming human, and he was telling me what they might be."

"Okay," Sam said, turning to face Cas properly. "What's your next one?"

"Well sometimes I get this… I don't know how to explain it. It's like a fullness in my chest and my heart feels... warm. Perhaps it's some kind of infection..."

"How often does it happen?"

"Usually when I'm around Dean." Sam's eyes widened.

"Do you feel like you can't concentrate when you're with him?" asked Sam.

"Yes," Cas said, suddenly looking concerned. "It's serious isn't it?" he asked.

"Dude," Sam laughed, "you've got it bad." Cas's expression grew more worried.

"Got what? Is it a disease?"

"No," Sam said, "I think you're in love with him."

"That can't be right," Cas said. "Angels aren't supposed to fall in love."

"You're not an angel anymore, buddy. Maybe your grace was the only thing stopping you from realising it before now." The sound of footsteps grew louder in the corridor and Cas looked up quickly.

"Don't tell Dean," he said hastily, just a second before Dean reappeared in the doorway.

"How's it going in here?" he asked.

"Good," Cas said, looking up and Dean. He paused for a second before glancing at Sam. "I think I'm beginning to understand things a little better."

"Good," said Dean. "Now, I'm exhausted, and you need to get some sleep." Cas nodded.

"I will."

Sam and Dean bade Cas goodnight, and walked together towards their own rooms.

"Who was on the phone?" asked Sam.

"Taylor Blake, remember him? He's been trying to gank a witch in Nebraska for a week. Cut off her head and everything and she just stuck it back on."

"That's impossible," said Sam.

"That's what I said. Couldn't find a damn thing in the lore about a witch that powerful, but we found a way."

"What did he do?"

"He pulled a Bobby."

"He put a witch through a wood chipper?" Sam asked, looking half horrified, half amused.

"Never fails." Dean said with a smile, stopping as he reached his door. He reached out for the door handle, but turned back to his brother. "Does Cas seem okay to you?" he asked.

"Yeah, he's okay." said Sam. "After all," he added carefully, "everyone has feelings they can't explain, right?"

"Right," said Dean, looking at his brother curiously. "Night, Sammy."

"Goodnight, Dean," he said, with a slight smile.

Dean got ready for bed, pulling on a white t-shirt and grey sweatpants, and climbed under the cool covers. He lay in the silence, but instead of sleep creeping up on him, Sam's words emerged from the quiet and began running in circles around his mind. Everyone has feelings they can't explain. That was exactly why Dean didn't like to pry too deeply into his own mind, because it will full of confusing, incomprehensible feelings that he was not inclined to tackle. It felt like an unnecessary risk, like poking a bear or picking up a grenade and giving it a good shake. As he lay on his back trying to force his unprocessed feelings back into the deep recesses of his mind where they belonged, he became very aware of the sound of movement still emanating from Cas's room. He tried to ignore it, but after ten minutes of muffled noise, he threw back the covers and walked to Cas's room. He knocked and opened the door before Cas had replied.

"I thought I told you to go to bed," Dean said, vaguely registering the familiarity of the words he had spoken so many times to Sam in the past.

"I tried."

"No you didn't. Get into bed, switch out the lights and shut your eyes, it's not rocket science."

"You're mad at me," Cas said, with an uncharacteristic sadness.

"No," Dean said, rubbing his hand over his face and forcing himself to soften his voice, "I'm sorry, I'm just tired. And so are you. You're going to make yourself sick. Humans aren't supposed to go without sleep, it makes you crazy."

"Okay," said Cas, climbing into bed. "Goodnight." Dean glanced back at him, looking small and sorrowful under the covers, and felt a wave of sympathy for him and his new mortality. Dean wished him goodnight and clicked off the light switch, traipsing back to his room, his legs heavy, his eyes beginning to burn with exhaustion. He lay down and listened, but now he could hear nothing but the soft hum of the pipes in the walls. He closed his eyes and felt himself begin to fade into the warm and comforting depths of sleep, but a few seconds later he was pulled back into the cold waking world by the sound of Cas's door creaking open, and soft footsteps approaching. Dean groaned and sat up, but the footsteps fell silent outside his door.

"Cas I know you're there. What do you want?" he asked, all sympathy evaporating immediately. Cas pushed the door open, but stared apologetically at the floor.

"It's too quiet," he said.

"It's supposed to be," Dean said, throwing himself back onto his pillow, vivid memories of sleepless nights with Sam rushing to the forefront of his mind, years of latent frustration appearing from nowhere.

"It was never this quiet in the bunker when I was an angel," Cas said, his voice low and serious at the end of the bed. "I could always hear you breathe."

"Cas, that's unbelievably creepy." When he opened his eyes again, Cas was standing directly over him. "For the love of -"

"Can I stay in here tonight?" Cas asked. Dean stared up at him and his sad frown. "I don't want to be in silence."

"Get in," Dean sighed, shuffling over slightly and lifting the covers to allow Cas entry. He felt Cas's weight on the bed, and without really thinking, he put his arm around him, pulling him into the warmth. Cas didn't question the arrangement, he just shifted into a comfortable position with his head resting by Dean's shoulder. Dean didn't speak for a few moments, he just lay listening to the sounds of Cas's breathing as it fell in and out of sync with his own. "Better?" Dean asked after a minute, his voice quiet and hoarse, but when he glanced down to Cas he saw that he was already fast asleep. Dean found his gaze lingering on Cas's peaceful face against his shoulder, and he felt a soft smile on his lips as all of those scary, inexplicable feelings at the back of his mind came forward into the light, and he realised that they weren't so scary after all. As he closed his eyes and pulled Cas's warm body closer to his, everything seemed to fall perfectly into place.