My glans has never been hard or “full” during intercourse or during masturbation except when I’m about to ejaculate. Then it swells and gets hard. This is the case even if I masturbate twice a day every day of the week.
During the December period I didn’t masturbate or do any PE for around 2.5 weeks, but I did do kegels regularly. Eventually I had to rub one out and my glans was hard, full and sensitive.
As the glans becomes full, it becomes more sensitive; that’s one of the physical reasons younger guys have more problems with premature ejaculation, and also one of the reasons why orgasms rapidly build in intensity.
I think a ton of guys begin to notice normal anatomical variations in their penises when they get into PE and mistake them for pathology (e.g., because they see the glans engorged or hard during jelqing or clamping or pumping, they begin to think its soft, normal state is actually abnormal, or they read about thrombosed veins and think that their dorsal thickening is a serious injury).