The blackening of the right side of the glans may be caused by frequent masturbation, penile injury, glansitis and other reasons. 1. Frequent masturbation: If frequent masturbation, it may lead to frequent stimulation of the glans, which may easily lead to localized pigmentation of the glans, resulting in the right side of the glans being black. 2. Penile injury: If the male penis is subjected to external violent injury, it may lead to localized soft tissue damage to the glans, and the right side of the glans will be blackened, which may be accompanied by pain and other uncomfortable symptoms. 3. glansitis: it may be due to the long foreskin, frequent use of irritating soap to wash the glans and so on, leading to bacterial inflammatory infection. When the local capillary blood gathering for too long, it may lead to the appearance of the right side of the glans black, and may be accompanied by local edema. If the right side of the glans is black, accompanied by pain, edema and other symptoms, you should go to the regular hospital in time to find out the cause of the disease, under the guidance of the doctor to take targeted treatment.