Just This Once - Wizards of Waverly Place, PG-13

Warnings: Incest. Spoilers for episode 1x11, "Potion Commotion."

Unlike every other time, Alex had no idea how she had gotten herself into this mess.

For a while, she couldn't quite place why she got so annoyed when Harper droned on and on about her crush on Justin. She knew why she was supposed to be annoyed—because he was her brother, because it was weird to hear her best friend talk about how amazing and cute and wonderful he was, and because, what she supposed to say? That it made her uncomfortable? It did make her uncomfortable, but not for the reasons that she supposed were common and natural and socially acceptable. These feelings were more barbaric and territorial. Defensive.

When Justin dated Miranda, Alex experienced a different feeling altogether—something closer to pride. Because all she could see was how similar Miranda was to her. A slightly goth version of herself with the added bonus of being of a different bloodline. But in the end, a lesser version. And substitutions wouldn't do.

That was how they found themselves this Saturday evening, sitting on the sofa together, watching a movie marathon on TV and not waiting for the phone to ring with calls from significant others that they no longer had.

The credits were rolling now, and Justin stood up and stretched with a loud yawn. "Bedtime." It was close to two a.m. Everyone else had long gone to bed.

Alex slumped deeper into the couch. "This was a perfectly pathetic way to spend my Saturday night." She was lying again. Her only defense against these feelings (the ones she told herself that she didn't have) was to lie and lie and lie.

He eyed her carefully, then smiled. "You loved it."

"Did not," she argued. But he had that goofy grin on his face and she had to give in. "Well. Maybe a little."

He sat back down, and seemed to hesitate before asking, "Why didn't you call Riley?" As if it were an afterthought, he quickly added, "Or Harper?"

"Harper's out of town this weekend. And Riley... I'm so over that." Alex grinned. "He wasn't good enough for me." She hoped this would provoke some sort of response in Justin, but he barely moved. And why should he? She sank back down in frustration.

Suddenly Justin laughed. "Sorry, sorry," he said in response to Alex's annoyed glare. "I was just thinking about that love potion spell."

She smiled. "That was pretty funny."

"You know," Justin said, a smile curling on his face as if he had just thought of a great joke, "sometimes I think you're still under that spell."

"What!" She tried to appear shocked.

"Well, you are pretty in love with yourself... most of the time," he teased.

"Well... I am a very loveable person," Alex said. "You can't deny that."

"Sometimes," Justin clarified. Alex smirked and another silence followed before he stood up again, this time with an exaggerated, clearly forced stretch. "Bedtime."

"Yeah," Alex said softly. "You said that earlier."

"And this time, I mean it." He began walking away. "Goodnight."

He was halfway across the room before he stopped and turned around. "Hey, Alex?"

She realized she probably should have been getting up and following him upstairs to her own bedroom, but something felt right about staying right here, waiting. For anything. "Yeah?"

He took a few steps toward her before asking, "Do you ever wonder what would have happened if I drank the other half of that potion?"

Alex swallowed, thankful it was dark enough that he couldn't see how flushed her face had become upon hearing that wholly unexpected question. "What?" she asked, partly from shock and partly because she thought maybe she had dreamed it.

"Never mind," he said, turning and heading towards the staircase again. "Goodnight."

She stared at his retreating figure, unable to move or speak.

An hour later she found herself in bed, this time staring at the ceiling, still turning it over and over in her mind. This was ridiculous. This was not about to consume her all night, and she walked briskly down the hall to his bedroom and stood in his doorway.

"Why would you ask me that?" she demanded. She kneeled at the foot of his bed, facing him. "You're making me have... thoughts... that I don't feel like having."

He turned and faced her, propping himself up against his pillow. "Sorry. I didn't mean to gross you out, I was just... wondering. It would have been hard to explain to Mom and Dad... and then Dad would have to tell us how to undo it somehow. And you and I would probably feel really weird afterwards... I don't know. It was just a thought." Alex didn't say anything. "Look, I'm sorry I brought it up. I didn't mean anything by it. I bet we're immune to the spell anyway."

She knew better than to say what she was about to say, but she said—whispered—it anyway. "I don't think we're immune."

There were no excuses for what was about to happen. There were no lies they could tell themselves in the morning. They were both breathing heavily now, and before she lost her nerve, Alex pressed her lips to his. As expected, he pulled away. "Alex! What do you think you're doing?"

"I'm—I'm showing you. Without a potion. Because—because you wanted to know," she said. "And because... I did too."

In the dimness of his room, she could see him close his eyes and shake his head. A long silence passed before he finally conceded, "Just this once. Just this once."

Maybe it only happened because it was dark enough that they couldn't really see each other—the eyes and mouths and noses that were so similar, almost identical—and she kissed him again, harder, falling on top of him in his bed, both of them touching and caressing skin that they had known their entire lives, but never like this.

Eventually—later than she expected—he gently pushed her away. "Okay. Okay. I think I get it now," he said, more confused than ever. A potion would have been far easier to explain than this.

She wished she could think of some way to comfort him, to tell him it was nothing, just a weak moment of curiosity, something, anything. They'd never mention it again. They could pretend it was a dream, but all of this was pretext—the hypothetical question, the weird thoughts, the promise that it would never happen again. Because soon enough, it would. Over and over.

This time, there would be no spell to undo the mess they had made, but unlike every other time, neither wanted out.