Author's Note: Just another oneshot from me! I got the idea while listening to the song "Checkmarks" by "The Academy Is...". I'm rating it "Mature" even though it's not really graphic... it's just because it's a bit... risque, perhaps? I really hope you like it, and just so you all know, I have another Dasey fic idea and I'm sure I'll be writing it within the next few days. So make sure you look for it! Oh, and feedback love! lol. Enjoy!

Casey glared across the table as her stepbrother as he shovelled loads of mashed potatoes into his plate. The rest of the family didn't seem to notice that he was robbing them all of the side dish, but Casey sure did.

"Derek, you're not going to eat all of that," she accused with annoyance, staring at his overflowing plate.

"I most certainly am," Derek shot back one eyebrow arched. He wanted extra mashed potatoes that night. And whatever Derek wanted, Derek got.

Casey narrowed her blue eyes at him as she stabbed her fork into her chicken without looking. "You know, someday you're not going to get what you want."

Derek knew that his stepsister's words held a double meaning. One that only he would get. But he just smirked cockily.

"I highly doubt that, Case. I highly doubt that."

Casey's eyes flew back to her plate and she stuffed a forkful of meat into her mouth, chewing angrily. She unfortunately knew that Derek was right. He'd get what he wanted.

He always did.

Later that night…

Casey hugged her favourite pillow to her as she lied on her bed in the dark. She had snuggled under her blankets and was staring at the door. She knew he would be there any minute now. He always came.

It wasn't long before the door opened quietly and a shadowy figure entered the dark room lit only by the moonlight streaming from her open window. The figure crept soundlessly over to her and the bed dipped as he sat down. She didn't stir as she felt her comforter being slowly pulled off of her.

"Casey…" his voice was soft. She felt his hand caress her cheek and involuntarily reacted, closing her eyes briefly at the gentle touch.

He smiled smugly at her reaction, knowing that she could never resist him. And he advanced her like a panther stalking its prey.

She felt his lips brush against hers and instantly she weakened. She hated how she always complied so willingly, so eagerly.

He ran his hand down her bare arm as he kissed her deeply. He felt her melt into his touch instantaneously, allowing him to bring her body closer to his body and his persuasive tongue to invade her warm mouth.

His experienced hands slid under her flimsy pyjama shirt to stroke her silky skin. She shuddered under the heat of his hands, her arms moving to rest against his bare shoulders on their own accord. She hated how pleased she was to realise that he wasn't wearing a shirt.

"Derek…" she moaned his name up into the air as his hands moved up higher under her shirt to rest on her bare breasts. His lips detached from her own only to pull the shirt up over her head and send it flying across the room.

"You want me, Case?" he smirked, feeling her breathing becoming raspy and audible.

Casey felt his hands pull down her pyjama shorts and she bit her lip. She wished so badly that he was wrong, that she didn't want him. That she didn't love the feel of his hands and his lips heating up her skin, making her feel alive.

That she didn't want to feel him inside of her.

She didn't move as he pulled off the last articles of clothing between them. Her panties and his boxers were bunched up together and sent sailing to land on her perfectly-organized computer desk. All she could hear was the sound of her heart beating wildly in her chest and the loud crinkling of a wrapper ripping as Derek hurriedly tore open a condom.

He rolled on top of her, pinning her to the bed, and she didn't fight him as his weight roughly pushed her body down further into her mattress. She dug her nails into his back as he swiftly entered her with ease. She gasped out at the feeling, even though she had felt it many times before.

She squeezed her eyes shut and wished she didn't like feeling her stepbrother pounding into her relentlessly.

"You like that, sis?" Derek asked knowingly as he began thrusting harder.

She felt a tear slide down her cheek. She did. She did like it. A lot.

He let out an animalistic grunt as he moved faster, his body now slick with sweat. He pulled her head up to him and swallowed up her gasps and moans with a passionate kiss. Her nails dug deeper into the flesh of his back and she kissed him back with just as much force.

He released her lips to hear her cry out his name in ecstasy as her hips bucked against him. He felt himself let go then, and the two of them collapsed against each other not long after, panting and straining for much-needed oxygen.

Casey felt her body tingle all over as she tried to calm down from her powerful release. He always did that to her. Every cell felt alive and dancing frantically like Mexican jumping beans. She finally opened her glazed eyes as Derek buried his face into the crook of her neck, taking in the mixed fruity scent of her shiny long hair and warm supple skin.

Although Casey unwillingly enjoyed the… other part… she appreciated this special time between the two of them the most. The few minutes where she and Derek would cuddle in the aftermath of their sin. She never felt so safe and adored than she did during this time. They would lie there in silence as their bodies tried to calm down, and he would press feather-light, gentle kisses all over her tingling skin.

They would remain that way until Derek silently released her from their embrace and fluidly moved out of her arms. She would watch him clean up and look around in the dark for whatever clothes he had been wearing. Sometimes she still found some of his clothes tossed in random hidden spots around her bedroom.

It would be the only evidence of their secret nightly ritual.

Derek would come back to her just before he left her room to kiss Casey so softly on the lips that she would want to weep. And then she would watch him creep out of the room just as quietly as he had come in.

And she would cry herself to sleep.

But, as cold and self-afflicted as it left her; she still anticipated the next night. Because Derek would be back.

He always came back for more. And she let him.

No matter how much she didn't want to admit it to herself, she would always let him.