I find these threads - the 'Does [sic] pleasures of self-sucking make you bi-curious?' is essentially the same question worded differently - interesting, especially when people get a bit irked etc. Just to be a bit contentious, possibly, I'd like to side with Ziggurat to some degree, at least in some respects: I'm not able to say if other people are hard wired 100% gay or straight, but personally I think it's quite possibly a kind of false distinction.
Basically there's this thing called sex, and you can have sexual relations of all sorts with anything and anyone - not that I'm suggesting you should - and then there's the issue of looking into all the different kinds of sexual relations one might have: love (and there's a whole debate to be had about what the hell that is), family relations (I don't mean incest here - that's another and weirder thread - I mean everything from power struggles between father and son, mother and daughter, alliances and threats, children becoming distinct and separate entities from their parents, all of that, right down to the bald fact that we're made of a sperm and egg combo, that we come out of mother's vaginas, and, if we're raised properly, we suckle at our mums teats), for procreation, for kicks, to play politics, to prove something to yourself or the world.
I don't pretend to know much Freud, but I have an inkling that he had a lot of interest to say on libido, and how we attach sexual energy to all kinds of seemingly unrelated things. So when Suse says "Let's even take it a step further, can you choose to find ANYTHING attractive? Your keyboard? Sexual orientation is not something you can choose," although I know what he/she means (sorry Suse, dunno yr gender!), I have to point out that I believe this is exactly one of the things that can happen in life with our sex energies. Hence all the weird kinks and fetishes people develop, from people who like the overly old or fat or thin or young, or one type of body or race or gender or dress sense, to people who like role-play, uniforms, scat, the list is endless. I love Robert Crumb and his sexual (and other) material, as it covers almost everything you might think of, and breaks all kinds of taboos, and seems genuinely human.
My love of sex drew me gradually but seemingly inexorably from Mayfair (UK soft porn) to hard core, which got me into cum-shots, esp big fat cocks spurting onto beautiful women's faces. A parallel but mostly separate development was my masturbation - which, in a Christian home, where smuggling porn in and being able to relax and enjoy it was tricky, was a largely gadget/prop free game for me - I don't know how or why, but, even before I was that aware of porn, I had the desire to suck my own wiener. I remember trying it, both just bending over whilst sat down, and also in the 'plough' position, as young as 11 yrs old. My love of the facial has now linked up with my quest to fellate myself (still 2 inches from being realised, after 20 years of half-hearted and unsystematic trying), and I frequently baste my tongue with my own goo these days.
Returning to the sexual identity thread: as a fairly pathetically unsuccessful teenage Romeo, I began to think I might be gay, but just not know it, or that my Christian upbringing had somehow smothered or obscured my possible latent homosexuality. With hindsight, and a few furtive gay/bi experiences under my belt, I can now report that what I felt intuitively back then holds good now: I'm drawn magnetically and biologically to women. How many times have I nearly caused fatal traffic accidents on the roads rubbernecking babes? Almost every day. Do I stop to look at builders? No. This said, I'm envious of openly bi or gay people I've known, because they seem to have a freedom I'm not laying claim to. As it happens, when that opportunity arises, as it does sometimes, most of the time I'm not up for it. But, like they say in jails, a hole is a hole, and sometimes I'm so horny I'd take my chances fucking firearms on a battlefield. I remember a gay bloke I met outside a club saying to me that he thought straight men were only ever "a few pints away" from being bi or gay, and I reckon he's not far out.
But, to bring this rambling rant back to auto-fellatio, or in my case the auto-facial: what do I think re the effect of self-sucking on sexual identity? I think, like the glorious craziness that is life itself, that it's a strange and complicated thing. Of course what we do affects our development, but exactly how, hmmm!? To me masturbation with my hand doesn't make me gay, nor does sticking a finger up my ass whilst masturbating. Tasting my cum seems like taking it all a lot further, but it's still just sex with myself, and, like Woody Allen - I love that man: not sexually tho', he's not my type

it's more a Platonic thing with me 'n' Woody - if I'm any good at sex, it's because I practice a lot on my own. Having said that auto-erotic activity isn't gay per se, of course one thinks of 'what if it were another mans cock'? And the realistic dildo I bought helped me take that line of thought further in the fantasy realm. But I actually worry more about how auto-eroticism might foster narcissism, or the desire to go to oneself and not the world or someone else for comfort etc.
And Suse, I'm not disagreeing with or arguing about things you said - esp not your brothers difficult times - but, re yr "Your keyboard?" comment, just pause for a moment and think about how central computers have become to a lot of modern people's sex lives! Ok, as a medium, and not the actual object of desire, but think where it might lead... To conclude, questions like these just pose more questions, and, albeit there are some sketchily outlined answers I have for myself above, I couldn't pretend to have answers for anyone else. Shit, all this thinking has made me wanna guzzle some home-brewed goo...