Breathing hard, Kevin rested against her, not entirely sure how he'd managed to remain standing with the combination of both of their climaxes, but he had. At least, he thought he had. He felt lightheaded, muscles weak, and adrenaline was now flooding his body for an entirely different reason, but he still refused to give in to it.
It was a long moment before he trusted himself to say anything that wasn't going to come out muffled in the heat of the moment, before he was sure he could speak and maintain his accent, much less figure out what sort of thing Alec would say right now. Because he had to be Alec, right up until the moment he Apparated away from here - wherever here was.
It probably wasn't actually very long, not long after getting his breath back at least, before his mind had come up with what to say. "Chas," he said, voice still rough from what they'd just done, words a bit slower than usual, partly from tiredness and partly for emphasis. "You are incredible."