Thank you, sweetheart! I gather from one of your previous posts that you're a cis-woman? Matter of fact, I'm a little bit in love with you after this one post.
I wish I was twenty years younger and single, so I could show you the respect, decency, and privately wild and adventurous life you deserve. But hang on to your self-respect, and keep the faith until the right one appears! Xoxoxo
So, a visitor to our little world, and a worthy soul to invest in a serious answer. Don't forget--you asked!
It would be hard to get a unanimous definition of "sissy," but if I could summarize what I've learned here, it's a cis-male bisexual (or bi-leaning) person who fetishizes feeling girlie and feminine, functioning sexually as a female (cock-worshiping and/or getting fucked), often (or always in some cases) wears female clothing and/or lingerie, is (at least) bisexual to the extent she adores cocks and cum (and we tend to think of ourselves as girls when we're sissy (which for some of us is all the time).
Some people pass briefly through this fetish on the way to becoming transgendered, but usually not. Still body-modification and feminization are a big part of the fantasy part of the fetish.
Theories abound (some dwelling on the negative aspects of the loss of "masculinity" and some on the positive attainment of "feminine" attributes), I guess defending on whether you consider masculinity something so wonderful it would be "masochistic" to trade it for "femininity," (an interpretation that sounds misogynistic to me!) or consider feminine attributes to be something desirable to strive toward). I'm solidly in the latter camp!
If you strip away the Domme/sub, BDSM play between my wife and me, we're basically a heterosexual married couple. But due to a combination of physical problems and that sex-negative rearing you described so well, she simply never could develop an interest in "normal" hetero (PIV) sex. She has a super low libido, wasn't sexually adventurous or motivated,and we had a very rough time of things for many years.
It's not a stretch to say few men would have stayed with her through those years. But I'm an engineer at heart. I'll be damned if I'll let any situation defeat me. I believe in solutions. My motto is "I'm for whatever works!"
Some years ago we began exploring alternative modes of sexuality, including power exchange (D/s), bondage and light S/M play, and costumes, etc. This got a spark, but not a flame.
But then one day I shared with her my lifelong fantasy of being sexually penetrated and fucked, and I wish you could have seen the look on her face! "Wait, you want ME to fuck YOU?" Light bulb!
About the same time I discovered a form of fetish pornography called sissy hypnosis, which is generally a form of dominant female erotic hypnosis focusing on various aspects of feminization, humiliation/degradation (a big turn-on for most subs) and some form of coercion into bisexuality.
This is mostly not classical hypnosis, though some of it is very effective at inducing a trance or trance-like state through a powerful combination of rapid-fire porn clips, captions (sometimes just subliminal), music and or a hypnotic voice track.
I can't say it "works" but it has coincided with the changes that were happening in my sex life, and helped to sustain my interest and commitment. I've always had bisexual leanings, and some homosexual experiences (mostly during adolescence), but was functionally heterosexual and monogamous.
It wasn't hard for me to develop and nurture some gender fluidity and to get off on the fetish of being a woman during our play time. What was surprising to me was how much I loved being fucked! And my happiest discovery has been these incredible extended orgasms from being fucked. Yeah baby--you could say this works!
These developments were a turning point for my wife. Outside the bedroom, not much has changed (other than a glow and a big smile). But she is now a sexual tigress, my Goddess in the bedroom! She has learned to orgasm reliably, and she usually has two or three powerful orgasms every time she's in the mood for it (which isn't every time we play--and as much as I don't understand that, I respect it). But now that I'm the fuckee, she's always in the mood for sex! Our biggest problem is that we can't get alone everyday for long enough to really do justice to our desires (we have two terrific daughters and other responsibilities), but whenever time permits we get it on for hours! Usually that involves me in bondage, but always in thrall to my Goddess, letting her give me her choice of pleasure or pain or both. She is in the driver's seat, she is the master and the fucker. I'm her little sissy slut, her property. She has a good time doing stuff to me, and I get to surrender my will to hers, and be totally submissive. In the bedroom. This doesn't carry over to "real life," where we're equal partners, but it sure does act as a powerful glue in our relationship outside if plat time!
I don't consider myself to have lost anything. "Masculinity" was never a prized possession. Being a girl sexually, while being a successful male in society, does not bother me. Just the opposite--it thrills me!
I have always adored and preferred the company of women, even though I'm very attracted to maybe 2% of males and extremely aroused by cock. In my experience femininity is an extremely desirable state. I've also enjoyed being a submissive and a bottom. But if this is masochistic, it sure is sweet suffering!