Its all in the eyes.  I know that most guys would check out the tight body and the taught muscles fighting against the restraints, but for me the fun is in seeing how his pupils get huge as my friends and I start to undress.  Observing the tears form in the corner of his eyes as we start to get him into position. The pleading look he gets when he fully comprehends what is about to happen to him. Then seeing them close tight as he is penetrated for the first time. You can follow the destruction of his manhood without ever looking away from his eyes.