Sounds Like
Steel

We Do Urethral Sounding

Sounding (also called Cock Sounding) is a form of Sexual Play, utilizing previously only medically used devices called Sounds, inserted into the urethra. Sounds can be made from Steel, Aluminum, Glass (Pyrex), Silicone and some specialized other materials. 
Primary to the practice of Sounding is Cleanliness. Not only for the Sounds, but with everything used with them. The Lubricant, the things we touch when we Sound, and ourselves.
Our bodies are not used to having anything other than warm liquids in our urethras. At first you may experience some slight stinging or other noticeable feelings. That doesn't necessarily mean there is a problem, but it should be a sign that maybe you Sounded for too long of a time or you might need to use a different lubricant.
Everyone is different, and some people don't enjoy Sounding. Some people enjoy the heck out of it. I can't explain what it feels like because it doesn't feel like anything else. I usually use the word Exquisite to define it. But you will need to learn to Listen to your Body. That's the only way you can progress and enjoy Sounding.
I often get asked if it hurts. My answer is always Not If You Are Doing It Correctly. We Guide the Sounds, we don't push them. We let them into our bodies, we don't force them in. It's a pleasure that only some people will ever find. Is it right for you? Only you can tell that by trying.