During erection , the glans of my circumcised penis , sometimes,is larger than the shaft and sometimes smaller. Even when my glans is larger, if I press on the glans, it becomes smaller. I feel my glans appears smaller on erection when the blood flow into it is less and larger when there is more blood flow into it. I have experienced that when the glans is larger, I have delayed ejaculation , and premature ejaculation while smaller. When I press on(squeeze) the glans while erect, I feel the blood goes down to the shaft and glans becomes smaller than the shaft. Are there any means to check whether there is enough blood flow into the glans during erection? I feel I have this problem since my adulthood. Is there any medicine to increase blood flow into the glans on erection? I feel I have enough blood flow into the shaft during erection, but not always to the glans. Even while there is enough blood flow into the shaft,is it possible that the blood flow into the glans is less? During erection and when the glans appears smaller than the shaft, if I press on the base of the shaft and tighten the grip there, my glans becomes much larger