I realize that this is an old thread, but it always feels nice to contribute my information.
My glans do not fill at all or much. The only instances where my glans have blood in them are:
Very little during a full erection. When I press my finger on the center of the top of my shaft at the bottom. With really good morning wood. When I kegel, or am having an orgasim(which is a bunch of uncontrolled kegels).
This doesn’t bother me much at all, but aren’t there suppliments that can be taken that would help the healing of veins or anything?