Author's Note: Another Dean/Castiel oneshot from moi. I had this sitting on my computer for a few weeks and I just decided to come back to it yesterday. I had this taking place somewhere in season 4, nowhere in particular though.

Rating: PG-15

Disclaimer: I own nothing.

Watching Dean sleep has always fascinated Castiel.

Dean's sleeping patterns were very odd, even for a human. To be honest Castiel felt the whole notion of sleep to be an unnecessary waste of valuable time but he understood its purpose for human survival.

Sometimes Dean would fall asleep as soon as he hit the pillow. This was usually after a tough job, or a long day on the road, Castiel observed. Other times Dean would feign the appearance of sleep, but still be as alert as he was during waking hours. Castiel found that this occurred most on the nights when Sam would sneak away.

At first Castiel's presence in the dark motel rooms that the brothers took refuge in was merely just out of necessity. Dean's dreams of his time in Hell were starting to consume him and it was just awful to watch someone go through that; the tossing, the turning, the sheen of cold sweat that covered his brow, it was not a pleasant image for Castiel. Seeing anyone suffer never was.

And that's when the angel of the Lord would step in. Sometimes he would emerge from the shadowy recesses of the room, walking silently as if on air, careful not to startle his charge. He found he only did that when Sam wasn't present. When the younger of the Winchester boys was there, Cas would simply remain undetectable to the human eye.

Regardless of the approach he took, a gentle two-fingered touch would be all that was needed to cast out the demons in Dean's dreams and fill them with peaceful images that would ease him off into a deep slumber.

Eventually though, Dean was able to fight off the Hellish dreams on his own, meaning Castiel's services were no longer required. Still he found that he couldn't resist the sleeping form of the elder Winchester.

Cas liked to think that he was keeping Dean company. He seemed to sleep better when someone was in the room with him, even if Dean wasn't aware that Castiel was even there.

The angel liked it best when Sam was gone, which started happening more and more as the war between Heaven and Hell waged on. He felt more comfortable when he was alone with Dean, and not just because Sam was slowly turning himself into a monster. The overall feeling in the room was just…different without Sam. More serene, one could say.

Castiel often wondered what Dean dreamt about. He could've easily found that out by sneaking into Dean's head and then erasing his memories of it, but Cas thought that would be too strange. He would leave the dreaming invasions to times of great importance, like when he was able to reach Dean no other way. So, for now, he was content with sitting in the darkened room, watching Dean's chest rise and fall with each shallow breath.

But that all changed one night in a small town in Illinois.

The night had started just like any other. It was raining. Sam and Dean had just returned from the grisly job of digging up some poor soul, and salting and burning it so the tormented entity could finally move on from this earth and into the afterlife. They were covered from head to toe in mud and look exhausted. Castiel caught Dean contemplating whether he even wanted to bother with a shower or just crawl into bed. Fortunately, Sam managed to convince him that a shower was probably a good idea.

After their showers, the boys participated in their usual ritual of consuming whatever alcoholic beverage they had on hand (9 times out of 10 it was beer) and television. This only lasted as long as the bottle did and then the TV went off and they'd hit the scratchy motel sheets and be out.

An hour after that, when he was sure Dean was asleep, Sam got out of bed, put on his coat and it shoes and snuck out of the room to go meet Ruby like clockwork. Many times, Castiel had been tempted to appear to Sam at that moment and stop him right in his tracks, but that would cause Dean to wake up and then Cas would have to explain why he had been there in the first place. And he would like very much to avoid such an embarrassing moment.

Something was different about tonight, though. Dean would usually pop up as soon as the door shut, and look over at the empty bed. He would entertain the idea of following his brother, but he'd be fooling himself if he said he didn't know already what Sammy was up too.

However this time, Dean remained stiff as a board, not even flinching when the door closed.

Castiel tilted his head in confusion. Quietly, he emerged from his shadowy vantage point and surreptitiously made his way over to Dean's bed, just to check and make sure that the human was breathing.

Much to Cas's relief, he was. In fact, the light fluttering of his eyelids told Castiel that Dean was dreaming. Castiel smiled slightly and allowed himself this moment to admire the sleeping form of Dean up close.

Castiel stood there, at Dean's bedside for a long while. His eyes wandered all over the hunter's body, mesmerized by how the faint light outside of their room played with his handsome features. Castiel found himself resisting the urge to reach out and touch Dean. To run his hands across his face and chest. To brush away the stray strand of hair that had fallen onto his forehead. Castiel wanted it all.

A twinge of sadness arose in Castiel's heart though, when he realized that this would probably be the closest he'd ever get to Dean in that way. But, he convinced himself he was content with that, thus suppressing the longing feeling that bubbled up every time he looked at Dean.

With an almost wistful sigh, Castiel felt that he was done for the night. Sam would be returning soon also so it was in his best interest to vacate quickly.

However, something caught his eye just as he was about to disappear into oblivion. Dean had shifted in his sleep, changing his position from lying on his side to his back. His hands had also changed, going from resting on the pillow above his head, to under the white sheets.

Cas thought at first that he had somehow awakened Dean. But that was not the case here seeing as he still had yet to open his eyes and say something rude and sarcastic to the angel about stalking people while they sleep.

But, Dean was a bit too busy for that. Castiel noticed under the sheets Dean's hands were moving in an odd upward and downward motion. Dean's breathing had changed too, coming in sharp gasps, with slight noises occasionally passing his lips, rather than his normally slow, steady breaths.

It took Castiel a few moments, but eventually he figured out what was going on and immediately felt embarrassed. Dean was dreaming alright, but this time not about quiet lakes and fishing off the dock.

Dean was dreaming about having sex.

"Mmm…Cas…"

Correction. Dean was dreaming about having sex with—

Wait.

Did he just say?

This was the first time Castiel could say that he genuinely experienced shock. He was now also even more embarrassed that he knew something that Dean obviously wanted to keep to himself. Well, at least Castiel assumed Dean wanted to keep this to himself. Otherwise he would have said something. Or maybe not.

Castiel had so much going through his mind. Was this the first time he had this dream? Was he ever going to tell Cas? Or maybe he just ate a bad hamburger before bed and the dream was just a fluke and Dean just didn't even realize he was doing it.

With all this running through Castiel's brain at about a mile a minute, he didn't notice that Dean's strokes had become faster and more erratic and that he was moaning and groaning and biting at his lip as the sheer ecstasy of the moment came crashing down on him like a wave.

No, Castiel's train of thought was derailed when Dean all but screamed the angel's named as he climaxed, arching his back and crying out with pleasure.

Castiel's face was warm with blush. He had intruded on such a private moment, how he would be able look Dean in the face again was beyond him.

A whole slew of new and strange emotions started to consume the angel and, knowing that Dean would now almost definitely be waking up soon, (seeing as sleeping in the sticky mess he had made under the covers all night probably wasn't the most comfortable sensation), he had to make a break for it. And fast.

And, as fate would have it, not two seconds after Castiel vanished, Dean woke up, swearing he could hear the gentle sound of wing beats echoing in the distance…

A/N: Reviews are love. Thanks for reading!