Guys with rock hard erections have excellent cardiovascular and nerve health. They will always have bigger dicks than the guys who can't seem to muster awesome erections. Rock hard erections have some inherent penile enlargement involved. The blood pump stretches your cockskin, stretches the tunica and forces blood into the corpus cavernosa stretching it's capacity and in turn enlarging the penis greatly.
Mandingo's cock is like 4 to 5 inches soft and stretches out to around 9 - 11 inches when rock hard... that is penile enlargement at it's best and most effective.
I pump all of the time and was drawn to pumping because my erections were getting bad in my mid to late twenties. Pumping has not improved my erections at all and if I did have excellent erection genetics I would be able to pump up to absolutely unbelievable sizes.
If your cock gets really hard, pumping will only be easier and more effective. I pump up as large as I do because I am dedicated and pump as smart as I can, my lack of awesome skin stretching erections works against me, not for me. :tongue: