Hey Bobcat, I'm sorry that you are struggling with this issue
I guess we all were sometimes in the situation that you've described. How did I feel than I can't remember.
But couple years ago when I was in army we have had public showers and off course who wanted could see you know "all".
Well some time later after that shower one of my room-mates came to me and just talked like: "oh I've seen you, you are one of those guys with small penises".
How did I react on that?
Well I tried to put him in overall picture and somehow not to be caught by his words, so I tried to laugh on his remark and by so to make it non-important. It helped me to be aware of his age (he was much younger of me) and to remember of some his inadequacies, there were moments when he needed my help and support so I took it like pure rambling on everything. I've seen him as scared and lost guy who tried to gain something by pointing into others "weak spots". To me such behavior is more or less childish and I've seen it like that, he was poor boy who was never out of his home for long time, he tried to pretend to be tough guy and soon my thoughts were shown as true.
I can admit that I don't like being naked in public places and I'm trying to avoid such situations.
I must say that I don't see at all need in comparing sizes and making remarks on physical appearance. There are things that we can't change. To be honest I don't have any clue why I'm ashamed of nakedness and I'm not proud to admit that.
But beside that I have more issues that bothers me when I don't feel like man enough, like when I'm in crowded place and somewhere in first row of some happenings. I don't like being spotted and watched by others, I feel too exposed and too nervous.
And what struck me from your post are these words:
"But when you lock eyes with a guy who has a bigger penis, and he sees that you have a smaller penis and he smirks at you because he knows he's bigger and better, how can you not feel inferior?"
It could be that all this actually is not about size but rather about beeing seen with such negative attitude and treated like not equaly worth person. Real question is what can we do to not let down to others under such situations and to feel good in own skin?
I'm sure that is possible to overcome this by stop sticking to some negative opinions about self, stop thinking about lost opportunities and trying to build slowly positive approach, step by step. We all need heavily to work to fight negative self image that is left in the most of us as consequence of abuse. We survived something destructive and traces of that destruction is sometimes visible on many different sides. Let's dig all those scars and let's revamp it from zero.
I hope some other guys would add something to this....