I asked this question because I hesitated trying a metal ring for several years because of the "ER FEAR". After a few years on EF, I have seen many references to incidents caused by cockrings directed to internet posts, but never actually read of any members who required assistance in removing a cock ring.
After carefully measuring myself, I purchased my first metal ring, and have had no regrets, and no trips to the ER.
I have a friend who is an ER doctor at a local hospital. I asked him how often he saw patients coming in with problems removing a ring. He stated that while he had seen quite a few males in ER who were wearing a cock ring, all but two were there for other medical reasons. The two that did present themselves with supposed inability to remove rings were frequent flyers, patients who visit the ER at least weekly with some medical issue which could not be detected by medical personnel or any tests. He stated that in both cases, ER personnel provided them with lube, and had patients remove the ring,,no big deal. Having said that however, he did say that there is a possibility of having a stuck ring, but it appears to be reported more often than it actually occurs.
He then asked that since I was asking him about them, was I thinking about getting one, or had a problem at some time removing one. I answered with some embarresment that I had just got one, and no I had not had problems with removing it. He just smiled and said "me neither", and then changed the subject.