Holy skin… I was using peweights for a too long period, and my whole head was numb! But the wrap was so comfortable that I did not recognise. Well, I was able to get circulation back before my dick was all dead. ;-) Not a good idea to wrap on a boner. Too much blood was trapped in the head. But it was a good hook, though….
Never ever a turtle again...
There are many causes of necrosis including prolonged exposure to injury, infection, cancer, infarction, poisons, and inflammation. Severe damage to one essential system in the cell leads to secondary damage to other systems, a so-called “cascade of effects”. http://en.wikipedia.org/wiki/Necrosis
Do not click on the link. The article contains a rather graphic picture of a hangers necrotic unit. :(