Essentially the vessels that carry blood to the organ stretch. If they stretch for too long they deform and remain that way forever. It's why doctors slit the penis to relieve the pressure so the vessels go back to normal, a scar is more optimal than a loose noodle.Does anyone have any info on how a priapism can cause penis enlargement? WWG said it's rare but possible. I tried googling it and couldn't find anything on the topic. Is it like jelqing where the internal pressure is supposed to stretch out the tissues?
And since this is a fictional game, let the dev have their fun. If getting a hard-on for more than 4 hours was beneficial we would have min/max-ed the shit out of that.