I've been personally curious about my penis curvature, also. I never associated it with excessive masturbation, because my curvature existed long before I discovered the blessing of orgasmic pleasure. Over the years of displaying my bulge utilizing various techniques, I believe that I've enhanced the strength, shape, size, angle of erect penis, and its curvature direction. From my earliest memories, I recall my mother teaching me to take care of my "tail". Lessons included: "always pull your skin back when you pee-pee", "wash your tail, and don't forget to pull your skin all the way back", and "don't play with it".
My earliest recollections of my erect penis never gave me any concern, other than the thought that I should go piss. I don't know how that thought was planted into my head, but my erection always disappeared after I pissed. My erection curved like a banana in a downward direction. My parents were divorced before I was two years of age, and I never had anyway to compare my penis to another until I first started changing into swimming trunks with friends at the pool. I don't recall ever observing another erect penis, perhaps due to the fact everyone else was circumcised, and their bare knobs just naturally stuck straight out, because they didn't have skin. I didn't realize cocks came in different sizes; their stubbies always looked the same to me with the exception of some knobs being larger than others. I related that to age differences, believing everyone eventually grew to the same size. Our cocks distinguished us from girls, and only had one purpose (i.e. expel urine).
My mother instructed me in proper dressing techniques, also. Besides learning how to tie my shoes, I had to change my underwear everyday. Often times I wondered whether she counted the number placed into the laundry basket, because I would be questioned about whether I changed, and pulled my skin back while washing before bed every night. Many times I recall having to display my efforts to my mother in front of my younger sister. Sometimes I wonder if she was trying to teach me the joy of masturbation when she would ask if I had been playing with myself, prove that I had washed under my foreskin, and instruct me to pull my skin all the way back so she could see.
Part of my dressing instruction included placement of my cock within my briefs. My foreskin was pulled straight down and penis tucked between my thighs within the underwear's pouch. Given my current knowledge of naturally, occurring nocturnal erections during sleep, and the daily sensations of my cock becoming hard whenever I needed to piss, I honestly speculate my mother trained my youthful penis curvature.
I believe I am responsible for training my banana curve to curve to the left following six years of jacking-off 3 times a day using the same hand. Awareness of my larger- sized penis kept me conscious of my partner's pleasure during intercourse. It led to the utilization of many positions, so she could experience stimulation to different areas of her love canal. I associate all the maneuvers with my ability to deliver multiple orgasms to my partners, and my personal pleasure as I felt their pussies clamping on different areas of my cock.
I'm not positive about how it happened, but about 5 years ago, my penis curvature changed almost overnight. I speculate it is due to a number of factors. I still masturbate daily in addition to keeping my wife of 32 years satisfied. My wife and I work different shifts, so I'm free to develop different masturbation techniques, and often times spend 2 or more hours edging before ejaculating. I tend to stimulate my cock exclusively with my left hand now. I've utilized cock rings to enhance my bulge appearance. I always dress my cock towards my right thigh despite its desire to be dressed towards the left. I've wrapped my shaft with elastic bandages with the intention of increasing the size of my helmet head, and I've experimented with penis pumps.
My penis now has the distinctive upward curve while erect. Most often my leftward curve is evident during early stages of becoming erect. If I've been diligent with practicing my Kegel exercises, my throbbing erection curves towards the right along with its skyward desires. Alas, it doesn't appear to be as long as it appeared with its downward banana curve, but instead of the flatter oval shape of my shaft, a fatter, circular shape exists. My foreskin retracts past the corona of my knob, leaving no doubt about my erect condition.
Personal experience with my shape-shifter keeps me observing others' whenever the opportunity arises. Such a pleasurable organ! Hope my sharing leads to others sharing their experience.