When he is fully naked (and you are still fully clothed), instruct him to lie on his back in the middle of the bed with his head on a pillow. It is important, during this early stage of the session, that you gradually increase the suspense by taking your time as you render him unable to escape your clutches. He will already feel quite vulnerable, being nude while you remain fully dressed, so we want to allow that vulnerability to build. Tell him to be a good boy and extend his arms and legs towards the corners of the bed so that you can tie him up and fulfill his bondage fantasy.