When I was 14 I had been masturbating long enough to have learned that different techniques produced different effects, and these included the appearence of my penis.
I always enjoyed the view of my naked body. As I got better at masturbating, I learned that different grips produced different orgasms, and that the appearence of my penis during and after orgasms was different. By the time I was 14, I became very aware of this. Basically I used two grips, light with my hand sliding up and down, and tight with the pecker skin being dragged along with my fist. I could last longer using the light grip, and usually did this when I could take my time. I could watch my pecker turn from pink to red, and after comming enjoy its gradual return to its prejacked color. Using the tight grip caused a great deal more swelling and a quicker orgasm. After comming, my penis had a sort of fluffy appearence with the head having a pouting look. It remained swollen for a good two or three hours. I didn't realize it but its appearence drew the attention of the boys in my gym class who began to notice my penis's different appearence when we had morning classes. Since they were all masturbating, they correctly assumed that when my penis had its fluffy look, I had masturbated before school. One of my friends invited my to spend the weekend with him to learn what I did to produce the fluffy look. I was surprised, but gave him a demonstration of the tight grip. He tired it, and produced the same result.