For me, it was partially about aesthetics. It’s not so much about size as it is about form, shape and proportion to the rest of the body; kind of like how a bodybuilder might look at how developed his traps are compared to the rest of his body. Ideally, it’s about getting my penis up to par with the rest of my physique. We can and do train just about everything else, including things that aren’t readily apparent — balance, aerobic capacity, voice quality and support, etc. — So why should the penis be any different?
The other part is about getting a well-rounded sexual ability. For me that includes things like male multiple orgasm (key sound techniques as well as reduction of the refractory period), knowing how to do a good internal and external genital massage, tongue exercises for cunnilingus and so on. PE is a natural part of that.
The bottom line for me is that it’s a part of being a well-rounded and healthy human being: to know yourself, and how to use, develop and maintain what you have, and what you are.
The women in my life haven’t been terribly supportive of the idea and tend to see it as an ego thing, sometimes going so far as to refer to guys who have developed some of these things as “freaks.” If that’s how they choose to view it, then that’s fine, I guess. Regrettable, but everyone’s entitled to value and view things as they choose. I know why I’m doing it — and I’m comfortable in that knowledge.