Okay, so this is one of the many derek/casey stories I've written since recently rediscovering life with derek and falling in love with dasey. So let me know what you think of my Dasey writing and if you want more stories (I've noticed a severe lack of new dasey stories!)

Right then, she should have known.

Because the thing was he never agreed with Casey.

He didn't think tofu was just as good as a steak.

He didn't think a mark on an English class presentation would define his future.

And he sure as hell did not think that brother and stepbrother was the same.

He couldn't think that.

Not when he saw her smiling at him. Or saw her dancing. Or heard the way she yelped his name.

But he lied. And he was the lord of the lies so he didn't blame her for believing him. Even though he wasn't at the top of his game when he responded, "Yeah… You're right". He almost, in a terribly reckless way – and reckless was also something Derek knew plenty about- wanted her to call him out.

Or maybe he had even wanted to do something crazy, like tell the truth. To tell Casey that the way he fought off her boyfriends wasn't his big brother instinct, and the way he stared at her in that babe raider outfit...well did that really need explaining?

Except he doesn't do feelings. He's Derek.

So he's pretty sure how this Derek/Casey thing would play out.

Fade in -

They would be fighting. – Who knows what about? It didn't matter. It never did.

Then he would kiss her. – because his resolve had finally crumbled. Maybe she would be wearing one of those short skirts that she'd taken to while dating max. Or maybe she'd just have said his name, like that, the way only she did. Der-ek! And this time he'd just lean in, the way he's wanted to so many times.

He isn't entirely positive how this next part goes -

Maybe she pushes him off, once the shock wears off of course, which he figures would be long enough to taste her, and trace her lips enough times to commit them to memory.

Maybe she slaps him? Sure, Casey is against violence, but all her rules have exceptions, and Derek Venturi is the exception to every rule.

Or maybe when it's been too long, and she definitely isn't kissing him back, he'd pull away. But he isn't sure that he would. So let's go with option one.

- Regardless it all leads to the same end.

After they stopped kissing, the rejection would begin.

He thinks she might say something about how presumptuous he is, or cocky if she's really angry, and then some stuff about feminism.

He's certain, that even though she probably wouldn't use the word incest, a lot of family and brother/sister and related stuff would come up. Because it's wrong. It's bad and wrong to kiss your brother.

And then, the nail in the coffin is that keener good girl Casey McDonald, would never, ever, ever, go for Derek Venturi.

And he would have to laugh. And pretend it was all a joke, and a prank. Because what was the alternative?

Derek Venturi didn't do heartbroken.

And she would be angry. And she probably wouldn't talk to him for a while. Maybe until they came home for Christmas break. And then she'd have to forgive him. Because they're family, right?

So he's pretty much shocked when it doesn't happen like that at all.

They're sitting on the bed in his dorm room. Like they do all the time, because after a few weeks he stopped pretending that her visits were inconveniences to him. He had to, because the truth was that they really didn't need to see each other anymore. Her dorm was on the opposite side of campus. And they didn't share a single class. And their schedules, between work and school, and Derek's refusal to wake up before noon (except on Thursday when he had intro to film. For the most part) while Casey went on a jog every morning at seven am, meant they never really crossed paths.

and she says "Derek?"

and he replies "yeah?"

and she asks "step brother isn't really the same as brother. Is it?"

and then he kisses her.

And no one pulls away (not for a long time anyway). And no one gets slapped. And no one gets rejected.

And he can't believe that after all this time the streak has been broken. Derek and Casey have agreed on something. But then it hits him that actually Casey agreed with him. So that's not really the same. Call it a small victory. Because he doesn't even need it (all that much) now that he has her.