Declan couldn't be sure if he actually fell asleep or not. Christian had long since transfigured one of his shoes into a pillow for Apollo, which amused the professor to an extent, considering he had not thought of it. As he watched, the Hufflepuff turned his other shoe into a pillow for himself and settled in. After that, Declan wasn't fully aware of what happened. Dom had more or less snuggled in for the night, and he decided it couldn't hurt to just rest his eyes for a little while.
When he opened his eyes again, he forced himself to lift his cheek from where it rested on the crown of Dom's head. If this wasn't such a strange situation, perhaps he would have appreciated the fact that she could feel comfortable enough to fall asleep around him. Beyond that, even, he was basically holding her as she slept, and that wasn't at all where he had expected to be when he walked into the Room of Requirement earlier that night. Or was it yesterday by now? He had no idea what the time was.
But a voice reached his ears and he didn't care about that anymore. Casey was quite curious, he noted. Perhaps that wasn't such a bad thing, though. After all, Dom was part of Casey's family. It made sense that she would be concerned.
Still, his eyes widened slightly at her choice of subject, but it wouldn't do to lie or ignore her. Not when a part of him still held out hope of fixing things. "Um, technically no, we aren't. I mean," he clarified, keeping his voice low and calm in hopes of not disturbing Dom, "it happened once. But..." She thought it was meaningless. "But we had differing opinions about what that meant.
"And," he tacked on, completely unsure why he would tell Dom's own cousin what he was about to, "I kissed her once afterwards, but it was basically a good-bye one. I don't think I'll be coming back next year. It's up in the air right now. After graduation, it's possible that we'll just... pretend it never happened," Declan concluded with a slight shake of his head.
He nearly shrugged, but glanced down and thought better of it. One corner of his mouth lifted in a sort of disappointed grimace, but he looked over at Casey again, half hoping she would tell him not to shove off or let it go without trying harder. Perhaps then he would actually consider that.