Disclaimer: If you recognize it then I don't own it.
Pairing: Cas/Dean
Warnings: Heatfic, Omega!Dean, Alpha!Cas, knotting, a/b/o dynamics, mating
"Want another beer?" Cas glances over at Dean and nods as the green eyed twenty-two year old gains his feet. "Alright." the movie continues as he heads towards the kitchen and the off feeling he's had lately intensifies. Catches him off guard and he stumbles slightly. Leaning against the wall and trying to figure out what's wrong.
"Can we have more popcorn?" Cas's voice drags him back and something clicks into place. He knows exactly what this feeling is and he wants to throw up. Or rub himself against Cas.
"Cas...I need to leave." he's trying to focus. Trying to ignore it as he presses against the wall. As far away from his friend as he can get because this is his fault and he's going to own it. But Cas gets to his feet and rounds the couch even as Dean keeps talking. "Seriously man. You're going to want me to leave...now."
Blue eyes narrow as Cas tilts his head to regard Dean. "What's wrong?" he takes a step forward still watching Dean whose breathing is accelerating. "Dean?" his tone changed to one of worry and he took another step forward even as Dean's whole body flinched.
"Cas...trust me. You're not going to want me here." his voice is strangled now and what Dean really wants is to throw himself at his best friend. To beg Cas to touch him. To fuck him. To knot him.
"I'm not letting you leave here like this. Something is wrong and you're not telling me." some steel managed to creep into Cas's voice and a whine escaped Dean's lips. His eyes widened in horror and he tried edging away. Moving along the wall.
"Umm. That's good. Right there. Stay." it only earned a raised eyebrow and a huff of amusement.
"Funny Dean. Really funny." Cas rolled his eyes and took several steps forward before coming to an abrupt stop. He breathed in and completely stilled, "Dean..."
A nervous laugh escaped and Dean's mouth snapped shut, "Umm...yeah Cas. There's something I...forgot to tell you?" he winced even as the words came out and he fought his body's reaction to the Alpha in the room. The Alpha who he'd had a huge crush on for years. Since they first ran into each other at Freshman Orientation. "I'm an Omega?"
Cas breathed in again and his whole body seemed to twitch towards Dean. "Are you going into heat?" his voice is rougher than normal and when Dean meets his eyes the Omega sees the blown pupils. How Cas is straining towards him but holding himself back.
"I forgot." he whispered still moving along the wall. A growl escaped Cas's lips and Dean stilled. Breathing picking up even as waves of heat started to wash over him. It had been years since he'd experienced a heat because he'd went on suppressants the moment he could legally take them. "My pills. I'm sorry Cas." Dean's voice sounded small and he started to trembled. Body hot and he could feel how hard he was. Pressing against his pants and another whine escaped. "I'm so sorry Cas. I'd never do this to you."
The Alpha stared, took in every single movement Dean was making, and wanted nothing more than to close the distance. He'd resigned himself to just being Dean's friend. To trying to find an Omega who made him feel the same way and this whole time the one he'd wanted was an Omega. A beautiful, kind, funny, caring and brilliant Omega who could out-drink and outsmart most Alphas.
"Dean...I want." his fists curled and he forced himself back a step. Cas growled at himself and tried to not react to the scent of Dean's slick. Of the Omega's heat. The smell filling the room. Filling his apartment.
But Dean's mind was getting hazy at best and he's leaning against the wall. It's cool and he just needs the heat to stop. Needs something but he doesn't want to ask for it. Can't.
Dean's staring at him and all of his self-control is snapping. Every single lock breaking and Cas is right there. An Alpha was right in front of him and he can smell Cas. "Cas." it comes out broken, "Need you." Omega gold is circling his pupils and bleeding through the bright green they typically are. The trait no longer suppressed by drugs.
It's all it takes before Cas is crossing the distance and burying his face in Dean's neck. Inhaling the scent of the Omega and growling low in his throat. But he was still holding back, "You don't mean it, Dean. It's your heat." even though he doesn't want to pull away. Really doesn't. Wants to claim.
Dean whined low in his throat and pushed into Cas. All dignity thrown out the window. "I've had the biggest fucking crush on you for years." his hands are digging into Cas's clothes, "Knot me Cas. Please."
Suddenly Cas is crushing their lips together, pulling Dean in as close as he can, and tasting the Omega. The smell of slick and heat and Dean filling all of his senses. He's tearing off Dean's clothes and feeling Dean's own hands struggling with his own.
They're naked, pressed together, and Cas is dragging Dean towards the bed. Every single part of him completely focused on his friend. The one he never thought he could have and now he's kissing him. Touching Dean, pressing into him and Dean's rocking up against him. They're sliding together and Cas easily pushes a finger inside Dean. Feels the slick coating his entrance and Dean is tightening around his finger. Wanting more. Need it because the heat is driving him crazy.
"Dammit Cas fuck me. Please...need it...need you." Dean moves trying to get Cas's finger deeper and the Alpha pulls away. "Please. Knot me Cas. Need you."
After what seems like forever Cas pushes into him and Dean arches up into the Alpha. "Hot. So hot." Cas starts moving. Hips snapping forward and Dean's whining, moaning and tightening around him.
"Harder Cas. Harder. Need your knot." it comes out between moans and Dean is frantically trying to meet Cas's thrusts.
"Mine. Mine mine mine. Dean." Cas kept going and he can feel his knot growing. Moving and thrusting until it finally pushes past Dean's rim. A sound punches out of the Omega as he comes, head thrown back into the pillows, mouth dropped open. His body tightens around Cas and the Alpha's thrusts slow until he rolls them. Dean's legs falling on either side of Cas's hips as he slumps down and a low groan escapes when the knot inside pulls at the change of position.
"Cas. Sorry I didn't tell you." the words are breathed into Cas's hot skin as Dean nuzzles against him. Cas filling him up and it keeps the heat at bay. Banks the fire and he just goes limp. Wants to enjoy this while it lasts because Cas is going to leave him. Has to after he's kept such a secret.
A warm hand rubs down Dean's back, "Did you think I would treat you differently?" Cas's voice is rough and that's what hurts right now. Now that he's buried deep inside his best friend and knotted together. That Dean didn't trust him. "Why didn't you trust me?"
Despite the protest of his body Dean leans up and stares at Cas. The gold in his eyes more obvious this close. "I've been hiding it for so long. And I just...I don't know. You're not like that and now I did this to you. Forced this on you. You didn't even get to make your own choice and I'm sorry." he took a deep breath, "I'll understand if you don't want to see me again after this." his eyes drop and he can't meet Cas's burning blue.
The crack is noticeable in Dean's tone even as Cas spills into him again and he wants to bury his face against Cas. Simply breathe him in and wrap himself up in the Alpha's scent.
"This whole time I thought you were an Alpha or a Beta." one of his hands reaches up and holds onto Dean. Soothing over taunt muscles and warm skin. "I thought I couldn't have you." a rueful expression stole over Cas's face, "But this whole time...I could have tried to court you."
"Cas?" he doesn't want to hope. Doesn't want to misinterpret what Cas is saying because he can't.
"I want you to be my mate. I've never wanted anyone else." part of Cas is happy they're locked together because he wants to get all of this out. Doesn't want either of them to run away. Another part of him wishes they'd have talked about this years ago.
Dean jolts and tries to move but Cas's knot tugs against him and he moans even as Cas spills deep inside him again. "Fuck. Cas." he closes his eyes and curses himself. This whole fucking time and he's wasted it, "You want me?"
"Why wouldn't I want you? I've loved you for years Dean." he pulls the Omega down into a kiss and Dean's fingers tug in the dark strands. He doesn't care, just wants this right now and forever, he's wanted Cas for so long.
When Cas's knot eventually goes down and he pulls out Dean just wants to drag him closer. He doesn't stop the whine escaping and Cas grins, "I'm making sure we have enough supplies for your heat." he moves across the room and out the door leaving Dean spread out on the bed. Covered in come, lips swollen, and staring at the door waiting for Cas to come back.