This is a lovely little device that has proved to be quite effective for my purposes. It was presented to me by an adoring sub in the hopes that I may decide to use it on him. As it turned out, he was too excitable for me to actually place it on his member. Every time I grabbed the flesh to place it inside the the hinged bracket, the offending member would start to swell. I finally managed to force it on, but he winced and cried and became totally useless. So, I showed some mercy and decided to save the device for a playmate that could relax into it, and not be too afraid of the pain.
Lucky for me, a suitable player did indeed show up.
The key to success for this particular instrument is for the male to be completely flaccid when it is placed on the shaft. I insist on being the one who places it on him. It is made of very heavy steel, and the force of gravity alone is enough to cause it to slide down, scraping the skin along the way, not the effect I want at the beginning of its use. So I ran a cord through it and up around the sub's waist. Now having a very heavy piece of spiked metal dangling on one's genitals causes one to experience a wonderful feeling of surrender (or so I have been told). The fun began when I gave my boy a few commands that caused him to have to move about and feel the weight of the device. It became even more fun when I flogged him. This started to turn him on a bit, which caused the spikes to exert a certain pressure. I eased up, not wanting to overwhelm him. Then I started up again, increasing then easing up again in a sort of torturous ebb and flow. After the flogging I allowed him a short break and the chance to show his gratitude by kissing my boots. Once rested, the real teasing began. I played with his body and told him naughty things. I stroked the head of his cock and giggled when he became aroused, because along with his arousal, he experienced excruciating points of sensation. He had to hold perfectly still in order to process this level of intensity. I waited, calmly absorbing his surrender. The spikes did not puncture the skin, so we kept on. On and on, I teased him relentlessly, enjoying his responses. His soft moans and whimpering pleas felt good to me. I wanted to give him a goal to work towards, then he would be freed from the evil device. He had to pleasure me in a very specific way, and still be able to endure the torture. Alas, this was asking too much of him and I could tell by his sweaty, quivering hands that it was time to end our game, but not before he found the key I had hidden on my person. He found it hiding under my strap on harness and I mercifully unlocked the little lock on that nasty device and allowed him to recover.