Its not postural, and circulatory has already been ruled out by a doctor's examination. In fact, it was the possible risk of underlying problems that led me to the GP (you forget, I also know medical stuff.. ). As I have type I diabetes I am at risk of circulatory and nervous problems but the GP seems to think that everything is fine. I was referred to an Andrology clinic (apparently, urology no longer handles this, its all andrology now, at least in our health care trust) and their examination seemed to suggest nothing wrong either (testosterone levels normal, circulation fine). Unfortunately, they did not want to do much in the way of examination involving things like MRI, they did it all the old fashioned way. However, I apparently have the healthiest circulation (based on blood pressure and testing of different pulse points) they have ever seen in someone my age.

Have never smoked, do drink but only to moderate levels. Diet and exercise could maybe do with some work at the moment as I have got into some bad habits lately due to lack of work (though when I am working I tend to eat even less healthily due to stress... )

Oh, and in case you misunderstood, the CR I mentioned was not linked to play or BDSM but a direct effect of the problem. i.e. it was not through choice. Probably phrased it badly.

Basically, as far as I can tell, it is either psychological (got into a rut, need something to shake me out of it - this has happened before, though never this bad and doing something different and fun helped a lot) or, as Twisted says, my blood sugars need a little tighter control in the evenings.