I’ve tried this a few times and I actually find it feels really good. I’m going to keep trying it albeit very carefully and never too long. Part of the reason is that I’ve also been doing the whole “iron crotch” weight hanging where you hang weights from the entire package (which is more about using your package as a handle from which to stretch and strengthen internal stuff as opposed to for making it bigger) and I’ve noticed what looks like increased vascularity in the scrotum (in a good way—i.e. more visible blood vessels on the scrotum, especially when clamping, but not like unhealthy-looking varicose veins).
If we can increase penis blood flow through clamping then why not testicular blood flow too? It might actually improve your fertility or even boost testosterone production. At first it does feel like you have blue balls but once you get used to it I find it feels really awesome. I also don’t think I’m clamping nearly tight enough or nearly long enough to actually deprive the tissues of necessary oxygen, plus I first wrap the whole package in a soft bandage to prevent the clamp pinching the tubes and other stuff in there. I agree, as far as having a bigger penis is concerned, it’s probably of little or no help, but I’m in this as much for increased health and well-being as I am in it for a bigger dick, so I think this route is worth a little more exploration.
Also, I’m no doctor and I do understand that the testicles are a very sensitive area, but presumably the vas deferens are not so fragile they will be easily blocked or damaged? In fact, according to online medical references, the vas are surrounded and protected by a layer of smooth muscle, so between that and my soft bandage wrap it seems the risk of damaging them would be minimal (though again, I’m no doctor, so I could be wrong).
Of course, anything like this must be tried at one’s one risk, so I’m not recommending anyone do it who doesn’t feel right about it, but I think people could also be missing something if we all totally deny any possible benefit.