She bit her lip after they'd pulled away, ignoring the tingling as her mind flew far and farther away. Alya had never been a liar or a cheater, and yet it sort of felt like she was both right now. She was supposed to be the best best friend that she could be for Marinette, and yet here she was, staring up into green eyes and wanting another kiss.
Alya moved away, ignoring or rather trying to ignore the look on his face; love shone where it shouldn't, and she knew better than to race forward and claim it. It was much easier to pretend that she didn't see it, that she couldn't read it, but she knew that look from her parents, from watching them kiss with curiosity burning in her eyes. She'd loved a good story, and she always thought that personal stories could light a fuse and touch hearts, so she'd paid attention as if they were Cinderella and Prince Charming.
Naturally, if they ever saw her or caught sight of her, she complained. She didn't think in ideals really, and so preferred if people never caught on to her quieter moments when her voice didn't raise and let people see what they want to see.
"Alya," Adrien sighed, "I think that we'll be okay." She remembers flashes of when they'd accidentally discovered each other's identity, before Ladybug could catch up to her as she was still balancing the issues raised by the Akuma, and so Alya had detransformed in a spot that she thought was deserted and Cat Noir accidentally joined her.
It rattled her cages that she could fall even harder for him after that, as if her feelings for Cat Noir were a perfect play on the chess game to win her heart, and it didn't help when she'd started noticing Adrien more for hearing his puns and occasional sass that rarely reached the ears of anyone that wasn't paying close attention. She'd stopped focusing on him for Marinette's sake, for trying to pair the two up, and gauge his feelings for Marinette, and then she'd sort of started focusing on whether he could like her more.
Alya hadn't been prepared for that reveal that day; she hadn't been ready to face all of those kinds of feelings head on, and so she'd been startled by how their lives had rapidly changed. Somehow it led her and Adrien to standing here in a quiet, deserted classroom, stealing a few supposed to be quick kisses before heading home or to wherever they had to be for the day. It happened too often for her heart to not sting in guilt whenever she caught Marinette staring at Adrien or gushing over him or even when she tried to support her bestie.
There was only so much that Alya could do when she and Adrien were both smitten with each other and when Alya was too ashamed to ever let them be public, too ashamed of her betraying her best friend, too ashamed of the guilt, and too aware that Rena Rouge and Cat Noir now flirted all the time much to Ladybug's constant frustration since she'd often had to get them to focus back on the task at hand.
The truth was, Cat Noir was the only side of Adrien where she felt like she could kiss him in public despite the hate of some major LadyNoir fans. Rena was the outlier, the wildcard, and while she accepted this readily enough, some days, it was hard to live with the guilt of being with the one person that she wasn't allowed to fall in love with in so many ways.