anytime
when you look at the penis, usually its a gorgeous shade of blue/purple, and you have to insert needles and draw out a total of about 400ml of blood. you start with a smallish needle and work your way up. then you have to perform surgery to reroute the blood from the penis so that they cant get an erection for about 3 months, then you can think about doing corrective surgery...if the penis isnt totally FUBAR and all the nerves etc are just destroyed
so, next time you guys have an erection lasting an abnormally long time, either have an orgasm (which will make it go down) or rush to the hospital before your blood congeals into lovely red jello
all you guys using viagra without talking to your doctor take note