An extra blood vessel under the coronary groove is mainly due to the bulging of blood vessels, which can be seen in the normal state of erection, but also in people who masturbate excessively. If the normal erection, due to the penis is rich in blood vessels, causing blood vessel filling, thus appearing under the coronary groove more blood vessels. This situation is a normal phenomenon and does not require excessive tension. Secondly, this situation can also be seen in the crowd of excessive masturbation, masturbation may lead to the surface of the coronary groove of the skin blood vessels varicose veins, causing the situation of blood vessels bulging. As the coronary groove is rich in blood vessels, there can be many arteries and veins, but penile erection mainly relies on arterial blood filling. So this kind of superficial varicose veins does not show any symptoms and does not cause discomfort. To summarize, an extra blood vessel under the coronary groove is usually not a cause for concern, and if there is any discomfort, you should seek medical attention in a timely manner.