A lot of men settle for coverage only when flacid. As the FS is stretched, the area of the glans that is covered start to return to what it would have been had the foreskin not been removed. The glans is supposed to be rosey and smooth, but years of rubbing against under has made it calloused.
Typically it takes about 2 - 3 years of fairly regular stretching to get complete coverage. That means covered while flacid and erect. Men that stretch 24/7 get done sooner but are probably is poorer health (don't go to the gym) or don't have a sex life.