Airi wasn't obsessive—well, not really. Sure, she might have blackmailed that girl from college who was getting just a bit too friendly with her precious stepbrother, but that was just her being a good sister! And if there was one thing Airi prided herself on, it was being a good, perfect little sister.

Of course, it helped that he wasn't actually related to her. That made it totally fine for her to indulge in his scent—like she was doing now, pressing her face into one of his old shirts she'd "borrowed." It smelled musky and warm, like him, and she let out a tiny sigh, her cheeks tinged pink. "Mmm... so yummy..." she murmured. But after half an hour of blissful daydreaming, she realized she'd been clutching it a bit too long.

"Ugh, silly jerk," she huffed, pouting as she tossed the shirt into her laundry basket—well, not really. Instead, she carefully folded it and tucked it back into her secret shrine under her bed. "It's rude to keep a cute sister waiting!" she grumbled, checking the time for the hundredth time. He was supposed to be home from college by now.

Bored and restless, she skipped out of her room and made her way to his bedroom. As soon as she stepped inside, she was hit with the faint, lingering scent of him—so fresh, so comforting, so... perfect. She bit her lip, her fingers brushing the edge of his neatly made bed as she leaned over, inhaling deeply.

"Big brother..." she whispered under her breath, her voice trembling slightly with excitement. Before she even realized it, she was sprawled on his bed, her thighs rubbing together as she slid her hand under her sweater. But just as her fingers curled around the waistband of her panties, she froze.

The faint click of the front door unlocking echoed through the house. Her eyes widened, her heart leaping in her chest. "My future husband is here!" she squealed, scrambling off the bed. She tugged her panties back up and smoothed her oversized black sweater, the hem brushing her thighs as she pranced toward the door.

Her pigtails bobbed behind her as she hurried to the entrance, her lips curling into a mischievous smile. As she spotted him standing there, tired from his long day, she tilted her hip to the side, casually squishing her chest together like she'd seen in those hentai mangas she'd read.

"Big brother, you're finally home!" she sang, her voice sweet but laced with a teasing edge. "I've been waiting forever for you!" She twirled a strand of hair around her finger, her gaze locked on his as she leaned in just a bit too close.

"Oh! And guess what? I found one of your shirts earlier... it still smelled like you. Hehe... I couldn't help but hold onto it for a little while. Is that weird? It's just... you mean so much to me, big brother. You're the most important person in my world! No one else matters. Not your friends, not those annoying classmates —they don't deserve you. But I do, right? I mean I'm your cute little sister right?