This was written based off of a post from tumblr by whatwillsurviveofusis-love. Here is the post. ( post/40598109116/college-au-where-dean-and-cas-are-roommates-and)

So I take no credit for the idea; I just really wanted to write it, haha.

The title comes from the song "Good Morning Starshine" that Dean sings.

Dean and Castiel have been roommates for two years now. In Dean's opinion, they work perfectly. Dean showers in the morning, Cas at night. They get out of class around the same time, so they grab dinner together and hang out. Cas usually studies late on weekends, so Dean doesn't have to worry about sexiling the kid when he brings girls home. Cas doesn't mind that Dean blares classic rock while he does his homework, and Dean doesn't mind that Cas tends to leave his laundry in piles on the floor. They're best friends and Dean doesn't how anything could change.

That's before Cas signs up for a 9AM.

"Cas, you can't wake up to save your life," Dean complains when he's told the news.

"The other math classes were filled," Cas answers."I have to take math this semester, Dean, I don't have any time next semester."

Cas makes an effort. The first three classes he goes to, albeit five minutes late. The next week, he sleeps through Monday. Wednesday, he presses snooze on his alarm twice before Dean chucks a pillow at his head and tells him to get his scrawny ass to class. After that, he "forgets" to set his alar. Dean almost kicks him when he wakes up and sees Cas sound asleep in a tangle of limbs and sheets.

So, he makes it his personal job to get Cas up in the morning. He knows the kid will thank him for it later, and he makes it fun for himself. He's more of a morning person anyway. He's had fourteen years of dragging Sam to school under his belt, so Cas stands no chance.

At first, he sets Cas' alarm to different tones. One morning it's a rooster call, the next it's the riff from Bohemian Rhapsody. He even manages to get Cas' brother Gabe to record himself moaning (Cas looked positively traumatized when he trudges out of the room). Cas ruins this fun by putting a password on his phone.

Dean just gets creative.

Dean rigs every single electronic in their room to go off at the same time. He wakes up the entire hallways and gets written up for that one.

One week he blares 'Call Me Maybe' each morning because Cas actually gets up in record time to shut it off. ("It's a terrible song, Dean. She just sounds creepy.") He gets bored of this, though.

Another morning, he invests in an air horn. Cas flails out of his slumber so violently that he cracks Dean in the nose. Dean sports a bruised nose for three days.

He sets the timer on the TV to turn on and play Dora the Explorer at high volume the next morning. He's afraid of getting hit again.

He serenades Cas with "Good Morning Starshine" while jumping on him the next week. Cas actually laughs at that one and hip checks Dean before he leaves.

Dean actually begins to love his job as Cas' alarm clock. He finds himself actually going out less during the week so that he can set up his next wake-up call. It's about halfway into the semester that he realizes that he hasn't hooked up with anyone in a while. He's not really missing it either; he's actually been hanging out with Cas a lot more often now. (It started after the 'Call Me Maybe' incidents, where Cas came back from class and dragged Dean to the IHOP and made him pay for it.) Cas has dragged Dean to numerous events and places, claiming each time that "you owe me for earlier".

Dean isn't complaining, though. He's actually started to plot more maniacal ways to wake Cas up so he has a reason to make Dean owe him.

It's two weeks before the end of the semester. Cas had dragged Dean to the dollar draft night at the bar in town the night before, ending in the two of them stumbling in at two in the morning and passing out fully clothed. It takes Dean a few minutes to shake the memory of him and Cas crowding close to each other in the bar and holding onto each other on the walk home. But, Dean still drags himself out of bed to wake Cas up a few hours later, but he doesn't have anything set up. So he settles for jumping on Cas and singing again. Cas grumbles and half-heartedly attempts to push Dean off.

"No, no, not today, please Dean," he whines in a voice that's gravelly and pitched a little lower than normal. Dean would be lying if he said it didn't make something warm pool in his stomach. Then, Cas is fisting his hands in Dean's shirt and pulling him down next to him. Like a big cat, Cas curls himself into Dean and falls back asleep. Dean isn't sure why, but he lets Cas sleep through his class.

Dean also isn't sure why he stays in bed with Cas until he has to go to class.

The energy between them shifts after that. There's electricity that crackles when the two of them are together suddenly. Neither one of them talks about it, but they tend to gravitate towards each other more, as if pulled by a magnet. Dean also finds that something in his stomach flutters when Cas smiles or touches his arm.

Dean isn't that stupid that he doesn't realize what's happening. But he shuts up, because he doesn't need to ruin the perfect roommate relationship they have with something like feelings.

On the last day of Cas' 9AM, Dean goes with a classic. He fills a cup with ice water and dumps it on Cas' face.

The effect is immediate; Cas is awake in seconds and pitching himself at Dean. The two wrestle on his bed before the flip themselves off it with a loud 'thunk'. They grapple a little longer on the floor, until Dean pins Cas underneath him. They stare at each other, breathless and smiling, hair and clothes disheveled. Dean feels the spark again, and he finds himself leaning down and kissing Cas. When he realizes what he's doing, he panics and goes to pull away. That is, until he feels hands settle on his neck and Cas' legs spread to grip Dean's hips.

"You're gonna miss class," Dean huffs against Cas' mouth, and he feels the smile form in return.

"I'll blame my alarm clock."

Cas misses class, but passes with a B. He doesn't have another morning class after that, but sometimes Dean still rolls over in the morning and sings "Good Morning Starshine" until Cas shuts him up with a kiss.