It started out a fairly quiet weekend at the Venturi-McDonald household. George and Nora were in Quebec for one of their friends' wedding, Lizzie was gone all week at soccer camp, Marty was spending the night at a friend's house. This left Edwin, Derek, and Casey alone for the night.

Casey had just finished skyping with Emily. Casey loved her best friend, but this talk made her extremely uncomfortable. Unfortunately their conversation mainly revolved around Derek, who Emily was slightly obsessed with. She kept talking on and on about how cute Derek was. But what was really making Casey uncomfortable was that she completely agreed about everything Emily had said even though she couldn't even think about it. Derek was her stepbrother. Fantasizing about him was wrong. She couldn't deny though that she hadn't done it before, and she was about to do it again.

"No I'm better off thinking about anything else." Casey thought to herself. She still felt dirty thinking sexually about any boy, but her own step brother? It seemed sick. Yet she couldn't deny her attraction. There was something about his witty charm that got her every time. He was a handsome little devil, that's for sure. Since when did masturbating ever hurt anyone? As long as she never acted on it everything should be healthy and fine

Casey looked at herself in the mirror before, taking off her red Harvard t-shirt and grey sweatpants. She looked in the mirror for a moment, looking at her black bra and panties. She then undid her bra as it dropped down to the floor, and stared at her breasts that every boy at her school talked about.

As Casey lied in bed she put her hand in her panties as she began to masturbate. She rubbed her clit in a circular motion, and kept thinking about Derek eating her out. She thought about having an orgasm, something that had not yet happened, despite having had sex with Truman five times. She knew she must have been getting close as her pussy was getting wetter and wetter. She would finally get one, not through playing with herself, but when Derek walked in…

Derek didn't mean to walk in, he just wanted to ask if she's seen his hockey stick laying around. But he forgot all about the hockey stick, when a stick formed in his pants, as he watched Casey- his step sister- touch herself. Derek didn't like Casey . He thought she was a snob and a bore. However he still was attracted to her. Her breasts were something out of a Girls Gone Wild DVD. She had perfect brown hair. Her curvaceous body was a sight to be seen. He found himself checking out his sister far to many times for his own good. About a year ago Derek had seen Casey walk out of the shower in nothing but a towel. He jacked off to that image almost every night since. This was unreal. Watching his horny step sister, made him realize that he had to have her.

Casey continued to masturbate as she thought about Derek , until she heard a voice.

"Need some help?" asked smirking Derek standing over the bed.

" Derek? GET OUT!" roared Casey as she used her blanket to cover herself.

" I don't know Case, I've been in here for three minutes and you seemed, like you were having a great time. Don't let me bother you."

Then it her. There was only one way to save herself from the humiliation. She looked Derek and straight in the eye, and catching him off guard she kissed him. Their tongues wrestled as she took off his shirt and he squeezed her famous breasts as their bodies fell on the bed.

Casey unbuttoned his jeans as Derek quickly kicked them off. She felt her step brother's erection sliding up and down her panties, as her pussy got moister and moister.

" Fuck Me Derek" moaned Casey. " Fuck me hard"

In response, Derek ripped off Casey's panties causing him to stare at her beautifully shaved vagina. Casey pulled off Derek boxers and chucked to the other side of the room. The two stared at each other for a moment as the two were now completely naked. Derek dove his head into her naval area, as he began to search for her clit. Juices began to flow from his step sister's pussy as he swallowed it with sweet delight. Then without hesitation Derek at entered her.

Derek was a little bit bigger than Truman, so she feared he might hurt a little. However, she realized that wouldn't happen once when she felt the sparks coming when his penis touched her vagina. She was so wet all she felt was pleasure.

Minutes began to pass. Derek started off by making slow long strokes, taking in the moment. He heard Casey moan "faster"

As he continued to hump her Derek warned "I'm gonna cum."

"Don't stop. Don't stop" was all Casey could muster.

"But I'm not wearing a condom."

" Don't care. It feels too good!" With that Casey raised her legs in the air held on to the bed sheets as hard as she could and had her first orgasm., wile yelling at the top of her lungs.

Seconds later Derek to orgasmed as he collapsed on her sweet juicy breasts Derek looked up at Casey, and said " Best sex ever."

"We're going to have to do that again. "Casey said in agreement., as she grabbed her perky tits. " But Derek, no one, and I mean no one can know about this. Not Sam, not Lizzie, not George and Nora, not Edwin…"

"Edwin!" gasped

"What about him?" asked a confused Casey.

"Casey we were yelling at the top of our lungs, he may of heard us."

Casey's jaw dropped in horror.

To Be Continued