Bloodflow into Glans

[narayan56]

During erection, the glans of my circumcized penis is,sometimes, larger 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 there is less blood flow to it and larger when there is more blood flow to it.When I press on the glans while erect, I feel the blood goes down to the shaft and glans becomes small. Is there any means to check whether there is enough blood flow into the glans during erection? I have this problem since my childhood. Can I use any medicine to increase bloodflow into the glans on erection? I feel I have enough bloodflow into the shaft during erection,but not always to the glans. If there is enough blood flow into the shaft, is it possible that the blood flow into the glans is less? I use medicine for blood pressure and cholesterol(Atenol,amlodipne  and statin tablets).