The bolt made no noise as I pulled it back. I didn't expect it to considering how well oiled it was but still I was careful. I doubt if he'd have heard much even if his ears were not sealed with the plugs I had inserted, with them in place he was in complete isolation a far as sound was concerned. He probably felt a slight shift in the air temperature but that would have been all. I came back about every half hour or so just to check up on him, to make sure he had been good. Good was a relative term here of course. It also meant "how horny was I feeling at that moment" as well as "was he grunting or whining or struggling" and the punishment depended on all or any of those things.
I looked at him, naked with a sheen of sweat over his torso. He was gagged with a very effective muzzle that cupped his chin, covered his mouth and was strapped over his head where it was padlocked at the back to a decently heavy steel collar. The gag that was an integral part of the muzzle was not long enough to continually affect his gag reflex, it was big enough in diameter to hold his tongue down and force his mouth against the pull of the chin cup but not enough to choke him. I'd strapped it up comfortably tight, comfortably for me that is. The collar was tightly clipped to the rear wall of the cell so that if he tried to turn his head to the side it scraped on the rough concrete surface. The cell was nearly two and a half feet deep, three from side to side, about eight feet high and simply made of rough concrete. The heavy steel door was made to fit tightly enough so no light could seep into this area when it was shut. A metal hoop chained at three points held his waist still whilst heavy manacles held his ankles to each side wall. His wrists were also locked in steel restraints slightly in front of him and out at about 45 degrees, then clipped tightly to each side wall. I'd fixed a soft leather parachute to his balls. This was smooth black leather on the outside although there were a number of small blunt spikes on the inside. They were of no consequence until, of course, it was pulled down and they started to bite. Fixed to the bottom of the parachute was a small bungee cord and fixed to the bungee cord was a small chain. This was attached to a hook in the floor, the pressure on his ball sack responding to whichever loop of the chain I decided to fix to the hook.
The only other items he wore were nipple clamps and these were what I was considering as I looked at him. He'd pissed himself. This was of no matter and I expected something like that after all this time. I'd filled him with over two pints of water through a funnel gag before locking him in place and if he was too good I'd not have so much fun. I gently ran the back of my hand down his chest. He moaned into the gag. Another point against him. I'd told him to keep quiet after all. I ran both hands up his arms to his shoulders, he breathed in lightly and quickly. Then I just stood there for several minutes and waited. I could sense him relaxing. I reached out in a single move and snatched the clamps off his nipples. He gasped and choked whilst trying unsuccessfully to scream into the gag. I liked that bit.
He would never know what was going to happen next. He was in his own black, silent world of pain and expectation. If I was feeling generous I would wait a few more minutes then put the clamps back on. This cruelly made the pain even more excruciating, if I was feeling horny or he had displeased me in any way like pissing on the floor I would tighten them before putting them back. This generally made him thrash and scream, as far as it was possible to do either in his position, for at least 30 seconds if not more before sobbing into the gag, his body going limp once more. I sometimes added to my pleasure by pulling the bungee chain one or two rings further down and hooking them off. This elicited more of a gasp and successive panting than a scream but was entertaining all the same.
Well, he'd pissed and moaned so it was a couple of turns on each clamp and a couple of rings of the chain. I turned each of the small screw heads in a clockwise direction. They would really be biting now, made all the worse by the fact that his nipples were red and tender, the blood only just having got back into them. I decided to put them on him one at a time after playing with his cock for a short time. This might make him feel safer, shame. He relaxed and slumped forward an inch or two, maybe thinking his ordeal was over as I fingered his bell end and helped his cock become semi erect. Every few seconds I would let go then repeat the action. He got harder and his breathing became faster. I sped up the wanking until he was thrusting his hips and his delightful 6 inches of flesh was bobbing about in front of him. I then grabbed the chain and pulled down. The gasp turned to a muffled cry and he unsuccessfully tried to bend his knees which made him choke on the tight steel collar. I laughed as I then reached forward and snapped a clip onto his left nipple. The choking cry filled the cell, not difficult I admit, although quite a feat considering the size of the gag. This was repeated as I clamped the second onto this right breast. The screaming gurgling noise was effectively muted by closing the door and bolting it. I'd be back later.