I thought that Clark almost looked turned on when Bruce scratches his cheek with that kryptonite spear. It made me want Clark with a pain kink who's just so amazed that anything can hurt him and it's the most exciting feeling ever for him. And who better to give him some pain and rough sex and kryptonite pressed to his throat than Batman?
Bruce/Clark, pain/kryptonite kink
Bit of bloodplay would be a bonus.