If you occasionally have a nocturnal erection, erection or masturbation can get to the nerves and blood vessels healthy and probably does penile physically seen very well. If you still can not get an erection at times when you'd like, the cause probably psychological. To find out whether your night still get erections, so you can rule out physical causes, you can "stamp test" done.
The stamp test is as follows:
Step 1: Find a stamp edge (edge to what is a sheet of stamps), a strip of adhesive paper or thin paper tape.
Step 2: Paste before retiring the strip quite tightly around the penis.
Step 3: In the morning make sure the slip of paper is torn. If so you have that night probably had an erection. Because the tape during sleep can tear or come off you have to test a number of nights (5-6 times) in succession to perform certain.
