This OS is inspired by this edit on tumblr originalsintuxedos .tumblr post/45431687299/au-klaus-gets-jealous-when-he-sees-his-girlfriend made by Originalsintuxedos.

It was supposed to be short and fluffy and it turned out to be long and smutty, I don't know why or how lol. I hope you will like it.

Thanks to Matt-on-Matt who helped with the grammar.

Klaus sighed in exasperation as he gradually approached his mansion. He could hear the music and the chatter from a mile away. He wasn't particularly thrilled at the idea of a party going on under his roof, but Caroline was so enthusiastic about it that he couldn't bring himself to say no. However, as he reached the door, he started to wonder if he had been right to give in to her. How many bloody people had she invited? He could detect at least thirty different voices and he was not even trying to count.

Klaus entered the mansion and growled when a couple of students bumped into him. "Sorry, dude," the student said casually over his shoulder, making Klaus growl louder. Dude? Really? Who were those people? Caroline had promised to keep the party small but from what he could see, there was nothing small about this. She was going to have to seriously explain why his living room had been turned into a dance floor. Where the hell was she?

Klaus started to create a gap between the groups of teenagers sticking together in the room, removing them from his way with a little bit more force than necessary. He tried to spot long blond and curly hair but there were too many people. His patience quickly grew thin, Klaus stilled and focused on the noises around him. Music (bad, if someone would ask his opinion), drunken conversations, giggles from a couple who was obviously making out in a corner, and then he finally caught it. Her laugh. Caroline was laughing. He could recognize her laugh amongst thousands of others. There was no sound as beautiful. Klaus eagerly followed the sound and stopped dead in his track. All of the sudden, the people invading his living room became the least of his concern.

Caroline was dancing. With Stefan. Her hands were slightly grazing his shoulders as his arms were loosely wrapped around her waist. They were animatedly chatting and laughing together. Klaus kept looking at them, glued to his spot, the anger quickly rising in his chest. A peal of laugher escaped Caroline's lips and Klaus had a sudden vision of him ripping Stefan's hands off of his arms as well as away from Caroline's body.

Caroline's body was his. Every inch of her was his. Nobody else was allowed to touch her. Nobody. Eventually snapping out of his trance, Klaus raced to Stefan and Caroline and stopped an inch away from them. Caroline turned her head to see who was invading their space, and her face brightened as soon as she saw Klaus. Immediately abandoning Stefan, she threw herself in Klaus' arms, sliding her arms around his neck and pressing her body against his.

"You're finally here," she whispered happily in his ear, kissing his neck on the process.

But Klaus didn't respond to her embrace. Taking her wrists in his hands, he removed them from his neck and pulled Caroline off of him. She frowned in confusion and looked at him, suddenly taking in his angry face.

"What's going on, here?" he asked furiously, looking alternatively at Stefan and Caroline.

"We're just hanging out, Nik," Caroline answered, a little puzzled. "I know I promised to keep the party small but all the cheerleading squad wanted to come and they brought friends of theirs and…"

"It looked like a bit more than that," Klaus cut her off harshly.

Realization suddenly dawned on Caroline and she understood that Klaus actually didn't care about the party. He cared about her dancing with Stefan. Stefan came to the same conclusion at the same time.

"Come on, you're not jealous?" he asked incredulously.

Klaus scoffed.

"Jealous? Of course not. Pretend I'm not even here," he hissed between his greeted teeth. With a last furious look to Stefan and Caroline, Klaus turned on his heels and went right to the staircase heading to his bedroom. If he found anybody from the party upstairs he wouldn't be held responsible for his actions. But there was nobody upstairs. Caroline had done a good job at containing the party to the living room, knowing he would be mad otherwise. Klaus briefly wondered how she had managed to keep such a big party totally under her control. But he knew that she could achieve anything she put her mind to. Caroline was a Queen. She was capable of anything.

Downstairs, Caroline threw an apologetic look at Stefan.

"Sorry, Stefan," she said quietly.

Stefan smiled. "Don't worry, it's okay. Klaus is crazy about you, he gets jealous. I get it," he answered reassuringly.

Caroline groaned. "It's not a reason to act like a caveman," she grumbled. "We were just dancing!"

"I know, Care, but you know Klaus. When it comes to you, he tends to overreact," Stefan declared soothingly.

Caroline sighed.

"Yes, I know. I should go talk to him before he kills half of the party," she said half joking.

Stefan laughed and nodded. "You're right, go find him."

Caroline followed Klaus' path and climbed the stairs to his room. She didn't bother to knock as she entered the room and closed the door behind her. Klaus was in front of the window, his shoulders so tense that she could feel the anger coming off of him.

"Come on, Nik, what was that?" Caroline asked a little sharply. "I was having fun with a friend who also happens to be your friend. Don't you think you are overreacting a little?"

"I told you to pretend I'm not here, Caroline. Go back to your friend and don't mind me," Klaus answered icily without even turning to look at her.

Caroline huffed in exasperation. "Seriously, what is wrong with you?" she asked furiously. "I was having fun, Nik, that's it. There is nothing to be jealous about. Does being with you mean that I can't have fun anymore?"

Klaus abruptly turned around to look at her. "His hand were on you, Caroline," he yelled. "HIS HANDS WERE ON YOU."

Caroline took a step back, taken aback by Klaus' anger. He had never yelled at her. Never. They had had some arguments in the past, and Klaus had raised his voice more than once but never like this. Never with his eyes black with fury. Never with his hands shaking due to anger. Never with his jaw clenched like this. Klaus noticed the step back that Caroline took from him and his heart clenched. He didn't want her to step back. He wanted her in his arms. He wanted her pressed so close against him that he could feel every curve of her body. He wanted her body melting in his. Klaus' anger suddenly vanished and it was replaced by utter misery. He wasn't worthy of her. She didn't deserve to have to put up with his temper. He knew the day would come when she wouldn't be able to bear his moods anymore.

"I can't lose you, Caroline," he whispered brokenly. "I can't."

Caroline's anger disappeared quickly at Klaus' words. He sounded so broken that her heart ripped open. He was not mad at her. He was not mad at Stefan. He was terrified of losing her. And he reacted to that fear the only way he knew. Caroline knew better than anyone the trust issues that Klaus was suffering from. He had been rejected so many times, he had been so severely deprived of love throughout his life that he was perpetually insecure about her feelings for him. It was like he couldn't believe that someone could genuinely love him and want to stay with him.

Caroline rushed to him and threw herself in his arms. The same way she had done when he had finally come home, she slid her arms behind his neck and pressed her body against his.

Klaus immediately wrapped his arms around her, pulling her to him and gripping her so tightly that he would have broken her bones had she been human.

"I can't lose you," he whispered again, the vulnerability obvious in his voice.

Caroline pulled back a little, just enough to take his face in her hands and to look at him in the eyes.

"You are NOT gonna lose me, Nik. Do you hear me?" she enunciated firmly. "There is NO way that I'm leaving you, NO way. I love you. Even when things are not easy between us, I love you. I love you so much. How can you doubt that?"

Klaus closed his eyes and leaned forward to press his forehead against hers.

"Really?" he murmured. "You love me? Even when I act like a jealous moron?"

Caroline rolled her eyes. "I do love you, you idiot," she grumbled. "And yes, I love you even when you act like a jealous moron. Nik, I love you more than anything else in the world. How can you not see that? How can you get jealous of Stefan of all people who is like a brother to me? It's beyond me."

"Forgive me, my love. I saw you with him and I lost it," Klaus whispered.

Caroline chuckled. "I saw that, yes. You have absolutely no reason to be jealous. Not of Stefan, not of anyone. It's you that I love. It's you that I want. Nobody else. Just you. Always. What do I have to do to prove it to you? "

Klaus opened his eyes and sighed. "He had his hands on you and you had your hands on him and it just…" Klaus' voice trailed off and Caroline frowned.

"It just what?" she asked softly.

Klaus shrugged. "I can't stand the idea of someone elses hands on you," he admitted.

Caroline shook her head. "We were dancing, Nik. His hands were barely touching me. Come on, you must know that you are the only one allowed to touch me."

Caroline tightened her grip on Klaus' face and articulated each word to let them sink.

"You are the only one who gets to touch me, Nik. The only one. You are the only one allowed near my body. Stefan might get to brush my waist while dancing but you are the only one who can do that."

Caroline dislodged one of his hands from her waist and pressed it against the curve of her breast. Klaus inhaled sharply and Caroline lowered his other hand to her rear.

"You are the only one who can do this. Do you hear me?" she asked a little breathlessly.

Klaus' eyes darkened with lust as he nodded and he started to move his fingers against the fabric but Caroline wasn't finished.

Moving his hand again, Caroline slid it into the front of her low cut top so it was on the same place than before but pressed directly against her skin this time. She did the same thing with the other hand, making it slide under the hem of her dress to rest against the back of her thigh. Klaus sucked in a breath and started to stroke the soft flesh.

"You are the only one who can do that to me," Caroline repeated a little hoarsely. "Nik, you are the only one who can make me feel what I feel when you touch me. Your hands… Have you any idea what your hands do to me? You just have to brush me to set me on fire. You just have to stroke me to turn me into jelly. Nobody else would be able to make me feel that way. I crave the feeling of your hands on my body. I don't want anybody else touching me that way. Ever. Only you."

Klaus suddenly snapped and backed Caroline down to pin her against the wall. Lowering his head, he crushed his lips to hers and kissed her like he was starving. Caroline wrapped her arms around his neck to pull him closer and kissed him back passionately. Klaus ravaged her mouth thoroughly until Caroline's knees gave in and he had to wrap his arms around her to secure her to him. Klaus only let go of her mouth when Caroline's moans became incessant and his eyes bored into hers. The pure possessiveness he held in his gaze made Caroline shiver. She would have a hard time admitting it but she loved when he looked at her that way. In those moments of pure animalistic passion, there was no gentleness anymore. Just the raw need he had for her. Just the raw need he had to claim her as his and to possess her.

"You are mine," he growled. "You are mine, Caroline."

Caroline swallowed. She would be lying if she said that it wasn't a major turn on to see him so desperate for her.

"I'm yours," she panted. "Only yours."

Klaus growled again and dove for her neck, pressing feverish kisses against it. "Nobody else gets to do that to you," he said huskily against her skin.

Caroline nodded eagerly in approval. "Nobody else," she confirmed between two moans. She knew in that very moment that there wouldn't be any teasing or any gentle love making that night. It was going to be rough and passionate. Klaus clearly needed to mark her as his and as much as Caroline loved when he was tender, this rough side of him aroused her terribly. Klaus always liked to be in control in bed, his alpha male personality fighting for dominance. However, he had never denied Caroline when she felt the need to have more control over their movements. He loved her far too much to deny her anything, even when it was going against his instincts. But tonight, he wouldn't have any of it. Tonight, things were going to go HIS way. Tonight, he was the dominating alpha male in all his glory and Caroline loved every second of it.

As if to confirm her thoughts, Klaus roughly ripped Caroline's dress from her body and her lingerie was immediately subjected with the same treatment. Klaus then lifted her from the floor and carried her to their bed, his lips still attached to the skin of her collarbone. Caroline kicked her shoes off just before Klaus sat her on the bed. Grasping her shoulders, he impatiently pushed her to lie down on the mattress. Gripping his neck, Caroline pulled him to her and feverishly brought his lips to hers. Klaus' hands started to roam hungrily down her body, stroking every inch of skin that he could reach, making Caroline arch against him. She impatiently tore his shirt apart and Klaus quickly removed the rest of his clothes.

"Nobody else gets to do that to you," he repeated as he closed his lips around Caroline's nipple. Caroline made a strangled noise of approval but it wasn't enough for Klaus. Releasing the hardening nipple he hovered over Caroline and tilted her head to him.

"Answer me," he ordered.

Caroline struggled to find her voice and finally exhaled. "Nobody else gets to do that to me," she whimpered more than said. Satisfied, Klaus went back to her nipples and firmly pressed his hand against her core. Caroline cried out and dug her nails into his back, arching against his hand. Feeling her already so soaked, Klaus plunged two fingers inside of her and curled them while he pressed his thumb against her clit. Caroline cried again, his name on her lips this time. How could she be already so close? It was insane. Klaus moved lower on her body and replaced his thumb with his tongue, making Caroline buckle violently. He curled his fingers again while licking and sucking at her clit, fervently devouring her. It was only a matter of seconds before Caroline screamed and convulsed against him, overwhelmed with the insane pleasure coursing through her body. Klaus made her come two more times, never stopping the movements of his fingers and of his tongue. By her third orgasm, Caroline was a thrashing mess in his arms. Klaus traveled up her body to find her lips again and swallowed the whimpers that were still coming from her mouth.

"Nobody else gets to do that to you," he articulated possessively.

Talking seemed out of the question for Caroline right now but she knew that Klaus wouldn't let her stay silent. Opening her eyes, Caroline fight to breathe and locked her eyes with his, shivering when she saw how dark his eyes were. "Nobody else," she panted. "Nobody else, my love."

Klaus dove for her lips again and resolutely spread her legs to plunge into Caroline. He stilled abruptly at her cry, fearing for a second that he had hurt her. But Caroline shook her head and feverishly pressed her hips against his.

"Harder," she pleaded.

Klaus complied immediately, slamming his hips down again. Taking her wrists in each of his hands, he pinned them above her head.

"You are mine," he growled.

Caroline moaned and nodded, mumbling something incomprehensible. She hoped Klaus would be satisfied with this answer, because she had no control anymore over the sounds that were falling from her lips. Klaus kept slamming into her, pinning Caroline to the mattress with his hips the same way he was pinning her arms above her head. Caroline couldn't move at all but the way Klaus was so completely taking control over her body was setting her every nerve on fire. She was at his total command and she had never felt so desperately turned on.

Caroline moaned again when Klaus quickened his pace and her broken screaming of his name made him growl. Releasing her wrists, he slid his hands to the back of her thighs and lifted her legs onto his shoulders. Caroline screamed at the change of angle and Klaus relentlessly pounded into her, angling his hips and hitting all the right places with each move. He gripped roughly at her hips, digging his fingers into them and marking them with his hold. Caroline clung to his shoulders, needing something strong to support her as she was inexorably reaching the edge.

Klaus looked adoringly at her face as she writhed under him, broken sounds falling incessantly from her lips. The only words making sense were "yes" and "please" and "more" and his name. At the sound of his name, moaned over and over again, Klaus felt a wave of contentment crash into him. She was his. It was his name on her lips. It was his hands on her body that made her writhe like this. And he was the only one able to make her scream like this.

Sensing his control snap, Klaus slid a hand between their bodies and brushed Caroline's clit. She was so close that it was all that it took. Caroline came violently, her whole body shaken with fierce spasms and Klaus' name on her lips. Klaus rode her orgasm, waiting for the last wave of pleasure to recede before he stopped holding back. He groaned when the pleasure hit him with the full force of a truck and he buried his face into Caroline's neck, mumbling her name as he finally exploded inside her.

Klaus stayed still for a moment, trying to come back to his senses while Caroline kept kissing his shoulders adoringly. He finally propped himself onto his upper arms to lighten his weight from Caroline. He then pressed a light kiss to her lips and looked into her loving eyes.

"Nobody else gets to do that to you," he whispered one more time.

Caroline smiled and lifted her head to kiss him.

"No, Nik. Nobody else. Only you."

Thanks for reading. Please let me know what you think, please, please, please. You have no idea how much I love reviews :-)