The 11 Best/Worst Vagina Tattoos Of All Time [Photos]

This progressed, within a week, to a constantly half-rigid penis, day and night. Men are advised to seek medical attention for an erection lasting more than four hours. During a normal erection, blood rushes into the penis through the arteries to build up pressure and later leaves through the veins. But in nonischemic priapism, blood continues to enter faster than it can leave, causing persistent pressure and a permanent erection. The problem resolves naturally 62 percent of the time, the researchers reported.