@johnfinch
Pretty much you are. I guess it would hurt if you clamped it down way too much.
The pressure you put on the urethra is the determining factor. The pressure doesn't have so firm as to be squishing the penis.
HTH

@johnfinch Professional sources advise that if used properly, not overused or ratcheted too tightly, there is little risk. As I wrote earlier, I have worn it 18 hours a day with no ill effects. The plumbing remains in perfect working condition. I’m not suggesting anyone do likewise though.
Note: It’s estimated that approximately 10-15 million clamps are sold annually.

@johnfinch

From my experience, irritation can usually be minimized by experimenting to find the right size combination and level of tightness—not too tight, but not too loose—and by periodically repositioning the clamp slightly forward or backward every couple of hours.

The risk of UTIs can also be reduced by emptying the bladder every hour or two, and by regularly disassembling and cleaning the clamp with soap and water.

@johnfinch
I use the Wiesner clamp and when I put it on, I don’t even remember it’s there. I clamp it as tight as possible, and I don’t feel it. I’ve been using it for at least three or four years. I seldom keep it on for more than two hours, When I forget, and I have it on for three hours. I start to feel it and remember that I have it on and take it off.

Never had any infection issues.