UC75, when I was a kid and a was able to retract or pull the foreskin back and forth during masturbation. I did not like that method. Instead, I would pull the overhang down and cup the tip with my palm and start wedging it. It would massage the hell out of the frenulum and at the same time stretch the foreskin while the glans remained safe inside while all this action took place. I did this and dry cum until the day I actually shot a load. I could very easily do this with a towel for easy clean up or through the pants/underwear. I think this method gave me a very long foreskin today.
When I was a little kid my foreskin would not retract. Somehow I never discovered your method, which sounds like much more fun. When I was eleven, I learned from another kid how to run my foreskin back and forth which brought to to dry orgasms when my little penis would jerk up and down as it attempted to ejaculate. This was done with the head fully covered as I could not retract. My first wet orgasm occurred when I was twelve. Retraction came later.
I think my childhood tugging gave me a longer foreskin today than I would have had if I had not done the tugging.