Title: Some Security and Two Heartbeats
Author: an-alternate-world
Rating: M+
Characters/Pairing: Blaine Anderson/Sebastian Smythe
Word Count: 3,005
Summary: GKM Fill. Sebastian watches Blaine at the counter, eyeing the way Blaine holds each of their coffee cups. He's been waiting what feels like an age but Blaine seems entirely oblivious, smiling and even laughing – laughing – with some other guy at the counter. Is Blaine cheating on him?
Warnings/Spoilers: None in particular.
Disclaimer: I am in no way associated with Glee, FOX, Ryan Murphy or anything else related to the FOX universe.

The title is from lyrics within Lea Michele's "You're Mine".

Sebastian watches Blaine at the counter, eyeing the way Blaine holds each of their coffee cups. He's been waiting what feels like an age but Blaine seems entirely oblivious, smiling and even laughing – laughing – with some other guy at the counter. He's not sure if they know each other, but Blaine seems so carefree that he suspects maybe they do. Maybe it's a friend of Blaine's from school or work, but it makes Sebastian's skin crawl. He's sitting here, watching this. What if he wasn't here? If they know each other, what are they like without an audience? Is Blaine cheating on him?

The thought makes his blood both boil and turn cold, and he flexes his hands in an effort to stop them balling up and decking this random guy across the jaw in the middle of a coffee shop. The fear of losing Blaine after so long fighting for him festers with the jealousy that Blaine is talking to someone else, looking at someone else, the way he used to look at Sebastian. It took him years to convince Blaine he was truly after a relationship rather than a single hook-up, or even a series of them, not to mention Blaine had to recover from the loss of his engagement to Gayface. Sebastian had always known it wasn't going to work, but Blaine was a little slower in picking up the warning signs.

But Blaine doesn't seem to have any trouble in picking up the flirtatious signs of this other guy as he laughs again and Sebastian has had enough. He snatches up their coats and scarves and nearly tips over his chair in the haste to stand up.

"Oh my God. Sebastian! Your coffee! I totally forgot because I got-"

Sebastian doesn't even hear the rest of it. He shoots the politest smile he can at the unknown guy, which probably borders more on an unpleasant sneer, and presses his hand to the small of Blaine's back to steer him out of the coffee shop.

"Aren't we going to sit down and drink the coffee?"

"No."

Sebastian takes the coffees and tosses them out as he begins to yank Blaine down the street. Blaine whines at the loss of his mid-morning caffeine fix but Sebastian ignores him. He ignores the sounds of protest when he crosses the road against a red light and the horns that blare when they nearly get collected by a taxi that refuses to slow. He knows he's putting both of them in danger, but all he can think of is shielding Blaine from the world before he loses his mind entirely.

Eventually Blaine falls silent and they're in the elevator to their seventh floor apartment. Blaine is fidgeting with the tassels on his scarf, his lower lip bitten between teeth, and it's all Sebastian has to not push the emergency stop button and shove him into the wall right there. Some logical part of his head reminds him there's only one elevator and he shouldn't do that to elderly Mrs Violet on the twelfth floor in case she needs to go out or get in.

So instead he unlocks the door and it slams into the wall as he pushes it open. Blaine is slightly more gentle as he closes it with a soft click.

"Bastian?"

Sebastian has already ripped off his coat and scarf, kicked his shoes into two different rooms, and realises just how hard he's breathing when he stares at Blaine still framed by the door. He manages a deeper breath, slightly calmer, and beckons Blaine closer. He can tell Blaine is wary, but he steps into Sebastian's bubble of protective space.

"Those coffees were probably cold because you wasted so much time talking to that guy," he says, his voice low as he tucks an errant curl behind Blaine's ear. Blaine shivers at the cool brush of his fingers as he removes the scarf first and then begins unbuttoning the coat. "Do you like rubbing it in my face that others are interested in you too? Do you like reminding me that I still have to fight for you?"

He pushes the coat from Blaine's shoulders and it falls to the ground. He can tell Blaine has started to understand his raging feelings from the widening of his eyes.

"You know I would never-"

Sebastian presses two fingers to Blaine's lips, the other working on stripping the bowtie from his neck and then undoing the buttons on his plaid shirt.

"You're mine," he hisses as he peels open the fabric, marvelling at the bare, smooth skin.

It gets added to the pile of fabric at Blaine's feet and he leans in, tilting his head to suck a hickey to Blaine's neck. Blaine whimpers, his cold fingers skimming under Sebastian's jersey and t-shirt and pulling up. Sebastian draws away for a second to raise his arms and have it removed.

"Mine," he says again, grabbing Blaine to his body and pushing him backwards to the bedroom.

By the time they've tumbled onto the bed, Blaine has kicked off his pants and underwear and gotten Sebastian's unbuttoned. He helps with their removal, snags Blaine's socks from his feet as well as removing his own, and then presses their bodies together. It's only when he's completely naked and against his boyfriend that he feels as though he can breathe again, that he truly feels comforted by Blaine's commitment to him.

Some of the fury dissipates as he finds Blaine's mouth, his hands threading into dark curly hair as Blaine's hands roam across his back. He can feel Blaine's cock swelling against his thigh and knows his is expanding too, grinding their bodies slowly into the mattress with the exchange of breathless moans and desperate kisses.

He breaks from Blaine's mouth, moving back to the pinked mark on his neck. He sucks against it again, feeling Blaine clutch at his hair. When he moans, low in his throat, he moves on, leaving marks across his collarbone, near his heart, his ribs, down to his hip. A patchwork of bruising that looks fucking gorgeous.

Blaine whines and rolls his hips towards Sebastian's mouth, encouraging his cock between Sebastian's lips. He runs his tongue over the slit, tasting the pre-come, tasting the musk of his boyfriend. He bobs his head, taking Blaine deeper and deeper each time, feeling Blaine vibrate underneath him until there's a sharp twist in his hair and the taste of Blaine floods his mouth, warm and slick and he swallows. He swallows until there's nothing left and the cock in his mouth is a little soft but still hard and Blaine is gasping and writhing beneath him.

He moves to suck hickeys to the inside of Blaine's thighs, leaving a trace of his teeth after he bites down to hear the beautiful groan Blaine makes. He's spent so much time mapping every inch of Blaine's body, learning what sensation creates what reaction, and he uses it to his advantage in times like these.

His lips find Blaine's again, letting him taste himself on Sebastian's tongue. He rolls them over, propping Blaine against his thighs. He's tan and flushed, his body littered with blooming marks that fill Sebastian with pride and increase his desire.

"Has anyone ever loved your body as much as me?" he asks, both a reminder to Blaine and an acknowledgement of his own insecurities that maybe, just maybe, he's not satisfying Blaine as much as he used to. Maybe that's why Blaine was flirting with the guy at the coffee shop.

"Seb…" Blaine looks lost for words, scooping up the bottle of lube and pressing it into Sebastian's hands. He straddles his legs wider over Sebastian's body, his desires clear.

"Well?" Sebastian prompts, tipping lube over his fingers and roughly pressing in two. Blaine's still loose from their early-morning rounds before the sun was up and he uses that to his advantage, scissoring the digits sooner than usual.

"N-No," Blaine admits, his hands resting on Sebastian's shoulder to keep himself steady, to improve his leverage as he starts to bear down on the fingers within him. Sebastian quickly adds a third, soaking up the moan when he begins to repeatedly tease that one spot within Blaine's body.

"Then why do you flirt with others? What do they give you that I don't?"

He's torn between almost snarling, and almost crying. He's spent so many years trying to win Blaine's affections and feeling so wholly underserving of it the entire length of their relationship. He was always convinced the shoe was going to drop at some point and Blaine would ditch him for someone better.

Blaine pushes his hand away and holds up his cock, wriggling until he's sinking down on it so fast that Sebastian chokes on the gasp of pleasure. It's not often they're bare, not often that he feels so completely connected. Blaine rocks his hips with a determination that Sebastian admires, but it's not what he wants. He doesn't want reassurance, he wants to mark, to claim, to own.

He flips them over and sinks back into Blaine's body, hitching strong legs over his shoulders and driving Blaine into the mattress. Blaine's eyes are like caramelised honey, dark gold above flushed red cheeks and lips.

"Tell me. Tell me what they have!" he says, almost a shout, but Blaine can't really respond because he crashes their lips together.

He thrusts hard into the body beneath him, maybe almost painfully. He can still see Blaine's bright smile to a stranger and it spurs him on, faster and faster as his kisses turn messy. Blaine's hand squeezes between them, jerking himself off. There's a particularly hard clench of the muscles in Blaine's ass and it makes Sebastian come, filling his boyfriend and sucking him dry. Blaine spills over his hand and stomach with a moan, but Sebastian is already kissing him again, lowering his legs to allow them to stay connected in a way that won't twist Blaine's spine into the shape of a pretzel.

"I love you," he whispers, the little boy in him seeking validation that someone, somewhere, loved him too. He thought love would be enough, but maybe it isn't for Blaine. Maybe Blaine is going to trade up regardless of how much Sebastian wants to hold onto him forever and-

"I love you too," Blaine assures, thumbing at the tears that have started to trickle down his cheeks, kissing at the corner of his eyes as if he can kiss it all better.

Sebastian pulls out when it becomes too uncomfortable, clutching Blaine to him fiercely as tears continue to leak free. Despite the mess, the sweat, the tears, he holds Blaine on his body until he begins to feel slightly reassured. Naked cuddling was the best cuddling for re-establishing a sense of closeness. Blaine had taught him that.

It's when he's calmer, when he strokes his fingers up and down the curve of Blaine's spine, that Blaine finally breaks the silence.

"I'm not leaving you, you know that, right?"

He doesn't answer. He's not sure how to.

"Seb."

Blaine sits up, his tone vaguely exasperated, as he finds Sebastian's eyes. Fingertips touch his cheek, tracing over the freckles on his face and down to his neck. He has an obsession with marking Blaine's skin with hickeys; Blaine has an obsession with mapping lines between his freckles.

"You know why I talk to other people?" One side of Blaine's lips tilt up. "Because I know that this," he waves between them, "will happen. You'll turn hot and growly and fuck me hard, and then afterwards we'll talk and you'll open up a little to me and I'll understand you a little better. I know how much you used to check me out when I was with Kurt, and I know how you never take your eyes off me when I'm talking to someone else. It's…flattering, I suppose."

Sebastian's brow crinkles at the confession. "You use my insecurities to get laid?"

"It's… No, it's…" Blaine flounders around and Sebastian knows that even if Blaine won't admit it, he is right in his assessment. At least in some capacity. He's not sure how he feels about it. "I know I could ask you to take me like this, but it's not the same. It's not as raw and real."

Sebastian glances away. The only reason it's so raw is because he's so fucking terrified of losing Blaine. It feels like a hole has been burned in his stomach. And to think that Blaine sets this up, uses Sebastian for rough sex because Sebastian get so scared he can barely breathe? It cuts so deeply he thinks he may have a permanent groove on his heart.

"Hey." Blaine shifts against him, tilting his head back so their eyes are forced to meet. "You spend all day wearing masks, remaining guarded and strong around me when deep down, you're too afraid to ask for the reassurance I'd so willingly give you. I could spend every day leaving you letters, kissing your lips, telling you I love you, and you would still doubt your worth, you'd still doubt me." Blaine runs his thumb over Sebastian's lower lip, and Sebastian can't help but kiss it and nip it. Blaine smiles sadly. "This is the only way I know that allows you to be vulnerable, just for half an hour, to get you to talk to me without all your prickles and barbs trying to keep me away from the heart you won't admit you have. It's the only way I know to get you to truly relax and allow yourself to express that you love me too and you're willing to acknowledge and accept my promise to be yours."

A fresh tear escapes his eyes as Blaine kisses him, long and slow. His grip on Blaine's waist shifts to his shoulder blades, holding them together, relishing in all the skin he can touch. He realises it's less about Blaine breaking him down to use him for sex but instead that it's to do with his own long-standing inability to express himself properly, to conceal how he feels because he's so afraid of losing it. He clings to Blaine's skin, his breathing stuttered around the dip of Blaine's curling tongue and firm press of his lips.

"You can't blame me for being afraid this is too good to be true," he mumbles when Blaine's kisses start to end, bumping their noses together as he gazes into too-close golden eyes.

"Then I'll keep reminding you, over and over and over," Blaine says, dragging Sebastian's lower lip between his teeth for a moment and making Sebastian's cock twitch with interest, "but you can't blame me for trying to get you to open up and trust I'll always be here, even if my methods suck."

Sebastian huffs and moves one hand to Blaine's ass, his fingers dipping between the cheeks to rub against the rim. He can feel the sticky warmth of his own come which has leaked out, and Blaine clutches at him harder, his eyes fluttering shut and his breathing faltering.

"You're mine," he says, and Blaine's nod is jerky. Sebastian shifts his hand, his palm brushing against Blaine's balls as he slides two fingers in and listens to Blaine's beautiful, shaky moan. He knows Blaine has to be sore but he also knows how much his boyfriend likes the filthy mess of their bodies, stained skin some primal thing that had seemed rabid and uncontrollable at first. "Stop flirting with other people to make me jealous."

"But-"

"I'll try to talk more," Sebastian whispers, curling his fingers. His cock is rapidly taking interest in the prospect of taking Blaine again. He eases his fingers in and out, coaxing Blaine into moving against him. "I don't want to have my insecurities thrown in my face again, okay?"

"O-Okay. I'm sorry."

Blaine gets halfway to kissing him before the change in angle makes him shudder. Sebastian adds some fresh lube to his cock and rolls his hips until he's breaching Blaine again, sinking into the heat again, feeling Blaine tremble against him again.

It's so much slower to allow more than enough time for Blaine's body to recover. Sebastian's glad tomorrow is Sunday, because he's fairly sure all the sex today will make it impossible to move in the morning. It's only when Blaine is basically sobbing because he's so oversensitive but it's not enough for him to come that Sebastian moves. He leaves Blaine on his hands and knees and takes him from behind, admiring the shift of muscles in his back and the sight of his cock disappearing between two fabulously curved ass cheeks that he has spent so much time touching and admiring.

It speeds up until Blaine is writhing against him and Sebastian reaches beneath them, taking Blaine into his hand. It doesn't take long after that for Blaine to come, and the clenching of his muscles around Sebastian sends him over the edge again. He wraps around Blaine's sweat-soaked body, shifting to the other side of the bed where there's less of a wet spot from Blaine's come.

"I love you," Blaine murmurs, stifling a yawn as the five orgasms Sebastian has lavished on him begin to catch up. He has to concede that a nap sounds wonderful and encourages Blaine to drape across his body, despite how filthy they both are.

"I love you too," Sebastian says, nosing against Blaine's hair and letting his lips linger on the heated skin of his forehead. He can feel when Blaine slides into unconsciousness, savouring the comfort he feels knowing Blaine is his and his alone.

He wraps his arms securely around Blaine, pressing their bodies together, and allows himself to relax beneath his boyfriend as sleep rapidly whisks him away.

GKM Prompt

Blaine and Sebastian have some rough and dirty sex, after Blaine flirted with some guy and Sebastian got jealous and possessive

~FIN~