I think you may be using to much tension? This happens to me if I use a lot of tension for to long time.
If I use low tension I always get a big flassid hang for several hours after I take it off.
Since you are just beginning to use it, I would advice you to use very low tension, and increase it over time.
I think you will get better gains this way, the homepages of the different extenders tells you to start slow but what they don’t tell you is that this will make the gainsbigger!
I only wish that someone would have told me this when I started using my extender.
It is very tempting to max out the tension so that the gains comes faster, but it dosent work that way.
I have been using my extender for almost 600 hours now (yes I am calculating the hours) and I have found that the growth comes in spurts, and it always seems to come after some days of wearing it with low tension.
Try wearing it at 600-700 grams of tension, and take a 5 min break every hour to get the blood flow back, I squese it, shake it, jelk it, and sometimes do a helicopter (insert smile here).
Kristian