youdontknowme I would expect belts with penis tubes to have a much larger range in which they are secure, but still wearable than something that needs to close against the skin tightly enough to prevent getting a finger in.
I think on that part you are wrong.
The penis tube has to be very tight otherwise the soft penis can be pulled out. But having the tube pressed tight against the body causes pressure spots and respective issues much more easily than a female belt does.
Because the female belt can be worn actually very tight even with some pressure on the genital area, because it is wide and flat, so the force is distributed relatively evenly across a larger area. The rest is basic physics: force per area = pressure. So same force (tightness of belt) but larger area on the female crotch guard is less of an issue because the strain on any given point of skin is much lower.
