Not in a locker room, but when I was younger and much smaller, I had a friend who loved showing off his cock, he would pull it out all the time, or show the imprint in his pants, or swing it like a pendulum in his boxer shorts, one time he even got it hard. It was fucking enormous and fat, and made mine look tiny, like a Vienna sausage compared to a big kielbasa.
I hadn't seen many other cocks in person, so his showing off gave me a little dick complex that lasted for a long time. Seeing that big cock always made me really aware of the lack of cock in between my legs, sitting on top of my balls, which were tightly packed together, I would hold it up like he did, except with my thumb and forefinger, whereas he could use both hands, and think about how much higher his went, how it could touch his belly button and my dick, I would wonder what it feels like in my hands, to wrap my palm and fingers around that big thick shaft , to walk down the hallway feeling the weight of that big dick hanging between your legs, seeing a hot girl knowing you could impress her by pulling out your dick. Mine can only dream of reaching that size. I felt fucked over in the genetic lottery, and obsessed over having a big dick.
Maybe I just wanted it so damn bad, and kept wishing so hard for it, but The Little Weiner That Could kept shooting for the stars, gradually stretching and growing even though it was so slow, I didn't really notice it. It's just amazing to me how much bigger it is than it was at one point. It seems almost impossible, something I never thought would happen, to actually be able to feel confident that I have a big dick. I've missed so many opportunities for sex with smoking hot chicks back then, because I was too intimidated, felt inadequate. If only I had the size and confidence I have now