Hey Lowepro,
I've been sounding for about 2 1/2 years now. In a pretty dedicated manner.
I started off with much thinner smoother objects and have gradually progressed up to the larger more gnarly things I'm showing you. There is absolutely some pain, some of which can actually be pleasurable, associated with this process. But if you stick with it, don't overdo it, and give yourself sufficient recovery time between sessions, you get to where any pain is overwhelmed by the pleasure.

I don't know how to describe how it feels other than to say I love fucking my dick. Each sounding rod has different sensations associated with it, so I will switch things up during a session. One thing I will say is that it's important to be really hard in order to maximize the experience. There's no point in sounding a limp dick.

Take a look at this GIF and tell me if you think I'm feeling much pain.

Wish I could attach a video. It's much more ... descriptive.