Author's Note: Hey guys, long time no update! As always, thanks so much to everyone who reviewed the last chapter! I hope you all like this one!

Song for the chapter: Switchblade Smiles by Kasabian

Switchblade Smiles

When Derek awoke, Amy was gone and he was glad. The night before, the night of Isaac's party, she'd headed straight for his room without paying her friends much attention. She headed straight for him. This should have been a sign, it should have deterred him, but it didn't.

She was pretty comfortable with him now, after only a week of seeing him on a regular basis – too comfortable for his liking. Last night, they had fooled around and she had done things that made him feel guilty about suggesting she go home, so he had let her stay. She slept in his bed and he worried that they were growing too intimate, despite the fact that although they had now slept together they hadn't actually slept together just yet. And that was perhaps the most troubling facet of the whole development.

She was on his mind constantly. It was all he could think about – his fixation had gone beyond mere desire and had transcended into need. He needed to have her.

And so, it wasn't easy for him to balance what he was feeling. He was very, very attracted to her, but at the same time he was strongly opposed to becoming anyone's boyfriend. He knew, though, that the title was a necessary sacrifice that allowed him to continue with what they were doing, and he most definitely did want to continue. He wanted to do more than just continue.

And so, he was presented with a difficult conundrum. Just how much of his freedom did he wish to compromise, and at what point was what he was doing considered to be morally depraved? "Morally depraved" was a harsh phrase, but somehow it didn't seem too far off.

For all intents and purposes, he was using her. He knew she was far more attached to him than he was to her, and it therefore seemed quite immoral to prolong their relationship when he really had no intention of putting any emotional investment into it. And he had a fair reason, he thought, for feeling this way. So what if it made him an asshole? He had been burned too many times before to risk it again. He was only doing what was necessary. He was only protecting himself.

Maybe he was only using her for sex. Maybe that made him a horrible person. But they hadn't actually had sex yet, so his degenerate plot had yet to be realized and his soul was temporarily safe from the fiery depths of hell. There was still time to change course, he just didn't know if he wanted to.

He decided to ignore the problem until addressing it became unavoidable. Pushing these thoughts from his head, he padded downstairs, only to see Isaac clearing the house of the last vestiges of the previous night's events.

"Good morning," Derek greeted tonelessly.

"'Morning. Hope we didn't bother you too much last night," Isaac said, a knowing smirk playing at his lips.

"I was busy," his cousin replied cryptically.

"I figured."

Derek sent him an unreadable look, before heading into the kitchen to make some coffee. "How many people were here?" he asked disinterestedly from the other room.

"I dunno," Isaac replied, raising his voice so that his response was audible. "A lot."

"More than usual?"

"Yeah."

"Since when did you become such a partier?" Derek's questions were concise and almost scientific; they held no judgment and seemed to be uttered merely for the sake of saying something.

Isaac shrugged, but Derek couldn't see it. "I dunno," he said vaguely. They dropped the subject.

Derek, mug of coffee in hand, eventually rejoined Isaac in the other room. He sat on the sofa and turned on the television, but his cousin staring at him put a damper on the experience. He looked as though he wanted to ask him something, but couldn't build up the courage to do so.

Eventually, Derek grew fed up and asked, "What is it?"

"Can I ask you something?" Isaac countered with a question of his own.

Derek nodded tersely and Isaac continued, "Do you think it's weird if I ask Erica's cousin out?"

The older of the two narrowed his eyes. This certainly wasn't what he'd been expecting. "Why, did you?"

"Yeah," he blurted out. "And now that I think about it, it might be weird. She was kinda hesitant and it makes sense why. It'd be like if Erica asked you out or something – I would definitely feel kind of annoyed with you."

Derek opened his mouth to speak, but Isaac continued, "I mean, we're obviously closer than Erica and her cousin – Meredith, her name is – are, but still…"

In an attempt to process this new information, Derek said, "So, you're telling me that last night you asked Erica's cousin out and she said yes?"

"Yeah."

"Well you've already done it, so what's the issue? I hate to break it to you, but you can't take it back now. Plus, Erica's dating Stiles and from what you've told me she has no problem flaunting it in front of you. I don't think you should feel guilty, if that's what you mean."

"Yeah," Isaac reiterated. "You're probably right. Do you think I should ask Erica about it before we go out, just to be safe?"

Derek shrugged. "Do what you want." Advice – especially brotherly advice – had never been his forte.

oxOxo

Erica and Stiles shared a plate of fries at a local diner over a conversation about the previous night.

"So," Stiles started, inelegantly smearing ketchup all over the clean white plate, "you dropped Meredith off at dance practice this morning?"

"Ballet," Erica clarified. She sipped her Diet Coke daintily as she watched him butcher the French fries.

"Did she have fun at the party?"

"I'm not sure," she admitted. "I couldn't get her to tell me much. I think she was talking to a guy for a while, but she wouldn't give me any details."

"Probably just someone on the lacrosse team," Stiles shrugged.

"We know a lot of people on the lacrosse team," she reminded him. "Like, the whole team." And Erica certainly "knew" more people than both of them cared to acknowledge.

"I see your point. But who cares, it wasn't me and it wasn't Scott or Jackson."

She locked eyes with him meaningfully. "It could have been Isaac."

"Isaac? Why would you think that?"

Now, it was her turn to shrug. "I don't know, he has a thing for blondes."

Stiles kept his gaze fixed on the food in front of him as he said, "Well, does it really matter? I mean, you guys are broken up – you're over him." The last part sounded a bit too much like a question for both their liking.

"Yeah, but still… You don't think something happened do you?"

Stiles resisted the urge to snort and said, "With your cousin? She seemed about as prim and proper as it gets. I don't think you have anything to worry about."

"You never know," Erica insisted. "Remember how I used to be?" Reminders of Erica's past – recent and not so recent – never really went over too well with either of them. The future. The future was all they cared about.

To be entirely honest, Stiles did indeed find it hard to stomach the thought of her with other guys. And she had been with other guys. Many of them. And he hadn't dated any other girls. He couldn't help but feel insecure, like he had big shoes to fill; or at least several pairs of shoes to fill.

And then there was the crippling fear of inadequacy. He was a virgin. She was not. They had been dating for a few weeks, and the question of sex was imminent. It was just a matter of time. And the longer they dated, the more he cared about her, and the more terrified he became. What if he was no good at it? What if he was embarrassingly premature? These were all very real possibilities. She, having been with so many other guys, knew the difference, and he doubted she wanted to have to bring him up to speed.

He pushed these thoughts from his mind and shoveled a couple more fries into his mouth. This was what porn was for – educational purposes. And with their one-month anniversary coming up in a matter of days, he was in dire need of some education.

When they were finished eating, he paid the check and the pair of them walked to his Jeep. As soon as they entered the car, Erica's phone started to ring.

"Hello?" she answered.

"Hey. It's me, Isaac."

"Isaac?" Stiles made a face of disapproval. He had never though of himself as the jealous type, but maybe he'd been wrong. "What's up?" she continued.

"So I – uh – I just wanted to ask you something…"

"What is it?"

There was a pause on the other end of the line, and for a moment Erica thought the call might have failed. However, soon she heard, "Yesterday… I met your cousin…" Aaand immediately she knew where this was going.

"Yeah?" she prodded.

"And I really liked her, we really clicked. I wanted to ask her out, but not before asking you first. Is it okay?"

"… Yeah, it's okay." Even to herself, she didn't sound very convincing.

"Are you sure?"

"Yeah, I'm sure. It's no problem. I'm with Stiles right now actually, so I can't talk for long. It's fine, though. Go for it."

"Okay. If you're sure you're sure."

She smiled, despite herself. She had forgotten how cute Isaac could get when he was flustered. "I'm sure. Talk to you later."

"Okay, bye."

As soon as she hung up, Stiles questioned, "What was that about."

"I knew it – he wanted to ask Meredith out."

Stiles' eyebrows shot up. "Wow, you really called that."

"Like I said, he has a thing for blondes."

"So you told him it was cool?"

"Yeah, why not… We've been over for a long time and we're still friends – I wouldn't want to stand in the way of a chance for him to be as happy as I am." She turned to him with a syrupy-sweet smile and gave him a peck on the lips.

Stiles scoffed through the kiss. "Lay it on any thicker and I'd think you were lying," he teased.

She broke into a genuine smile, laughed, and said, "Well, our one-month anniversary is coming up soon. I guess I'll be able to better judge just how happy I am then." The suggestive wink she shot him did nothing to quell the misgivings he'd been having earlier.

Changing the subject, he questioned, "Are you pissed that your cousin didn't tell you it was Isaac she was talking to?"

"No, I understand why she wouldn't want to tell me… She'd never even met him before so she might not have even known it was him for a while."

"Well, in any case, I think it's good what you're doing. Very mature."

She laughed again and replied, "Because you're such a good judge of maturity."

"I am!" he protested with a wide grin.

"Whatever you say," she said with a roll of her eyes. She looked out the window as he drove away, trying to hold back traces of hostility towards her cousin. It was petty, everything that she was thinking. Isaac wasn't choosing Meredith over her – she had broken up with him. And now, now that guys were throwing themselves at her, she had chosen to be with Stiles. She was on top. She was winning. She had no reason to feel inferior.

Author's Note: Let me know what you think! Derek isn't just being a dick, I promise! He's just had his heart broken too many times before :'(