I got into this quite a few years ago and shared it with a couple of friends. When I'm really horny it feels good and can work some serious magic with the nerves in my cock. But to me it is more of a state of mind kind of pleasure and can be a huge turn on and feel good because of that. I hope that makes sense, lol. Just random insertion doesn't really feel good to me, like a masturbating sensation would.
When I get over the top horny is when I crave a good-sized sounding rod down my cock. Very few seem open to this because to the stranger it seems brutally painful and understandably so. But, it isn't. A guy's urethra is a tube, or hole just like his asshole and can accept something of proper size inserted in it.
It's been a while since I sounded. The last purchase I made concerning sounds were for flexible, beaded sounds that a hot friend introduced me to several years ago. They can feel really good going down.
What I'd like to try on myself or a friend, is to insert a sound slowly in his cock while he's taking cock in his ass.
I bet that combination could be mind blowing.