Warning Condituioned Clampers only
Fructis:
You should not have any testicular pain from clamping the shaft. Do not clamp behind the balls. What we mean by jelqing the clamp is precisely what you said, only you may have to loosen the clamp a click or two to get it to move, but if the engorgement is holding and the clamp is not riding up the shaft just leave it alone.
The following is pretty intense, and should not be attempted by beginner clampers:
If your dick is fully erect and an engorgement is clamped off after a while the clamp may sort of ‘ride up’ that is the clamp will feel like it is slipping a little toward the tip as you lose some of your erection. If left alone your erection will subside a little, and this is fine for mild or beginner clamping, just let it ride up and let the erection subside. Most of the engorgement will stay whether you are completely hard or not.
But for more aggressive clamping, once you are more conditioned you can keep a better engorgement by jelqing the clamp. When you feel the clamp start to ride up, take the tips of the four fingers of each hand and place them on either side of the upper edge(towards the tip) of the clamp and press the clamp down toward the body. You may have to loosen the clamp a click, or you may not, it is better if you don’t. Try it first without loosening the clamp. As you press the clamp down toward the body, kegel in blood and the engorgement should swell and your dick will become harder. Once the clamp is all the way against your fat pad, click it tighter if you can. (This is where most guys break their clamps) If the clamp is already as tight as it will go you can keep the tight engorgement and hard erection by keeping constant pressure against the clamp pressing it deep into the fat pad. This is a bit more work than passive clamping. Eventually it will tire out your fingers a bit. Next time use a little more wrap and you probably won’t experience this riding up of the clamp.