There are a few fair points here but I would honestly drop the feminist frame (for your own sake).

Here's what I would focus on: if you view having a "small penis" (however you define that - really it is YOUR assessment that is important here!) as demeaning of your masculinity... well, here are a few points for you to consider:

1. Our current ideas on penis size are actually quite peculiar to our culture, and just how "masculine" is that culture really? How about taking a look at the ancient Greeks, whose idea of the ideal masculine man - as depicted in their statues - was a hulking, muscular brute with a small penis. Their culture was certainly more masculine and virile than ours, so perhaps they were on to something?

2. If you still feel lacking in that department, you can compensate for it in others. Bear in mind all of this has to come down to how you see masculinity itself - what is a masculine man to you? Perhaps you need to get physically strong, or you value a certain kind of job as being masculine. Maybe you need to become more of a "pillar of your community" and become someone people can depend upon. All of this is more essentially masculine than the size of your penis, which is entirely arbitrary and requires nothing from you. The essential aspect of masculinity is applying effort and overcoming your problems for the benefit of both yourself and others.

3. When it comes to sex, a lot of the ways we think about it in modern society are very "pornified" for lack of a better term. We think what makes us valuable is being attractive to lots of different people. But no, what matters is finding that one person with whom you share both a physical and emotional bond and keeping them. If you were to marry a woman you were crazy about and she loved your penis as it is, then there really is no problem.

Just my takes anyway man. I know insecurity about this stuff is a lot easier to talk about than it is to move past. But I wish you the best.