How safe are penile constricting devices?

It is true that ‘penile constricting devices’ works, but at the same time they can be dangerous if they are left on too long. When a man has a full erection, to use the ring, he hooks his two index fingers into the ring and expands it as much as possible and rolls it down to the base of his penis and leaves it there. This constricting ring traps the blood in his penis, so he is able to sustain his erection longer. It is advisable not to leave it on for more than twenty to thirty minutes. While the ring is on, there is no circulation of fresh blood bringing oxygen and nutrition to his penis, so after a while, the tissue in his penis starts to die, and that is not desirable at all. Getting it off can be uncomfortable too, as he must hook his fingers under the ring to expand it.
Dr Rajan Bhonsle
Sexologist