Probably more aware of the undercurrents and sharply drawn lines in the room than either of the two humans, Crowley allowed himself to be pulled nearer, but didn't try for more. In the end, Kit was John's and John was Kit's and he was only privileged to be able to share a bit. It was more than he'd had in a long while and he was genuinely grateful.

Crowley had never taken a turn as an incubus, but one hears things around the water cooler, so to speak. Instinctively knowing that he wouldn't be allowed to touch John the way he wanted to or be more intimate with Kit than he had been

(undercurrents and sharply drawn lines)

the demon finessed the energies of the room a bit; not enough to really be noticeable, but to just enhance the pleasure of his companions. He would let that be his contribution as he wrapped his arms around both of them, kissing the back of Kit's neck and shoulder, and frotting against her sweat slicked skin, eyes half open to watch John's face.