Acid Rain
The door to Suguru’s dorm room slammed open, with Satoru immediately taking up the empty space, a wide grin on his face. It’s the first time Satoru’s been on campus today, his morning spent on a mission near Kyoto if Yaga is to believe, and Suguru was elated to see him. Satoru seems to think the same, for he immediately shuts the door and jumps on the bed, aiming for directly in between Suguru and Shoko and inadvertently crushing Shoko’s medical textbook in his wakeーnot that she cared.
The boy grabbed both of them by their shoulders, dragging them in against his sides, and it’s then that Suguru smelled it.
The same rain and wet fur scent, but this time, stronger. Far stronger.
“He finally scented me!” Suguru’s mind blanked out at that, his nose betraying him as it took a few deep breaths, the scent that was undoubtedly from another alpha filling his nose completely, and Suguru hated it.
Satoru should only smell like Suguru, he’s his, isn’t he? He’s Suguru’s omega.
Or at least, he thought he was.
Or: Satoru's reeked of another alpha for months now, and Suguru goes a bit crazy because of it (the alpha responsible is someone he never would've suspected)