Drip. Drip. Drip. Drip.

The persistent sound of water dripping kept Castiel awake, the noise loud, a constant distraction from the land of dreams.

He'd been human for a few weeks now - long enough for his body to have recharged enough that he didn't fall asleep at any given moment, on any given surface - but he hadn't had to sleep through any noises. Well, he hasn't had to try falling asleep with a constant background noise.

A dog barked in the distance.

The former angel sighed.

After a few hours, he was so exhausted that he fell to sleep, but when the sun came up, early the next morning, the rays tore him from his slumber.

Four hours, was the amount of sleep he got.

'Well, Dean lasts on four.' Cas thinks to himself. 'I can too.'

—

He's groggy the next day, his voice gruffer than normal. He meets up with the Winchesters, helping them on a case, that is in the town he is staying in.

Neither brother comments on the bags under his eyes, and Cas pretends that he doesn't notice their looks.

—

That night, the only thing keeping him up is the sounds of the couple in the room adjacent, moans and groans permeating through the thin walls.

He presses his ear against the opposite wall - the one separating himself and the Winchester brothers - and concentrates on the sounds he can hear over the couple. He can hear shifting, a shuffle of bed sheets, and deep, even breathing.

Cas falls asleep that night, leaning against the wall, lulled into slumber by the sounds - but only after the couple next door had finished.

—

They wrap up the case that day, and drive back to the Bunker, arriving around dinner time.

The three of them ate pizza, stuffing themselves full, and Castiel fell asleep easy that night, his food coma happily pulling him into slumber.

—

The rattling of pipes is what causes Cas' next bout of wakefulness at night.

He escapes to the library, finds a book, and curls up on the sofa the boys had put in there.

He falls asleep with the book opened on his lap.

When he wakes, he has a crick in his neck, and a sore lower back.

—

Cas discovers 'self-abuse' when surfing the internet on Sam's laptop. Dean has taught him how to delete his history, and so he absorbs as many details he can about the apparently pleasurable experience - especially the fact that it can leave you tired afterwards.

—

Castiel's experiment worked wonders. He got to sleep easily every night - no matter the volume of the noises reverberating around the room.

It was all going well until Dean walked into his room one evening, while the ex-angel was carrying out his nightly routine.

With wide eyes, the blond ran out the room, apologising profusely, slamming the door behind him.

The noise summoned Sam, who raised an eyebrow at his panicking brother, who was leaning against the door to Castiel's room, breathing heavily, eyes still wide, still muttering apologies under his breath.

By the time Sam opened Cas' door, the man had sorted himself out (uncomfortable in the jeans; zipper pressing painfully against a particularly hyper-sensitive area), and the long-haired moose had no idea what had just happened.

"I'm not even going to ask." He stated, shaking his head as he made his way back to his own room.

—

Cas doesn't get much sleep the night of the incident. He's cranky during the day, and the fact that Dean wouldn't speak to him at all that day only further lowered his mood.

—

That night Cas doesn't even think about his normal routine, instead his worry about Dean pulling him into slumber.

—

The next day, with only stilted conversation between the ex-angel and the blond hunter, passed by slowly.

Sam was pissed at the tense atmosphere, and decides to force them to talk.

So, that night, he locks them in a closet - a tiny thing, with barely enough room for one man, let alone two.

—

"I'm sorry, I really didn't mean to walk in on you doing… that…" Dean flushed red, glad for the darkness gracing the room.

"It's fine Dean, I should have locked the door."

"Still, I should have respected some boundaries." There was a brief beat. "Uh, any reason you were, y'know?"

Castiel tilted his head in slight confusion, but then he realised what was meant. "Oh, I found out that it helps me get to sleep."

"Oh."

"I've been having some trouble getting to sleep with the noises that can be heard from my room - pipes rattling, for instance. If I exhaust myself slightly, I get to sleep easier, and then I get a longer nights sleep."

"You've been having trouble sleeping?" Dean asked, worry lacing his voice.

"Only with noise. I think I retained some of my sensitive hearing when I fell."

Cas saw the green eyes look at him in sympathy.

Unexpectedly, Cas could feel the other man lift his arms, wrapping them around him in a hug.

Not knowing what else to do, the ex-angel returned the hug, gripping back as tightly as the hunter was holding him.

The late hour, combined with some of Cas' residual exhaustion, and the steady beat of Dean's heart beneath his ear, caused the ex-angel to fall asleep against the blond's chest.

Dean just laughed, gripped slightly tighter, to keep the dark-haired man upright, and gently knocked on the door behind him, whispering, "Sam."

Getting the message, the younger Winchester opened the door, and Dean somehow managed to gather the blue-eyed man into his arms, carrying him to his room.

When he tried to deposit him onto the bed, Cas refused to let go, so the hunter laid down next to him, shifting to get the covers over the pair of them.

—

In the morning, Cas is bright-eyed and chirpy, hovering over Dean as he wakes.

"Hi." Cas' deep voice seems less deep.

"Hey." Dean's is the opposite, seemingly more gruff than normal.

Instead of getting up, Cas pillows his head on the blond's chest, nose brushing against chin.

Dean could get used to waking up like this.

"How'd you sleep?" the hunter enquired.

"The best sleep I've ever had, if I'm honest."

Dean can feel the heat of the ex-angel's blush on his chest through his thin t-shirt.

"Well, we could do this again, if you want?" the hesitancy was clear in Dean's tone, but his face was completely serious.

"I would." Cas smiled up at the man. "As long as we can do it in your room. I would really like to try the mattress that remembers you."

The blond burst out laughing at the comment.

"Of course." He smiled, tilting his head down to meet the ex-angel's lips.

He tasted like heaven.