I feel like I read somewhere in the thread that he was in sex tapes with Jin? Or maybe not?
Yeah, he was in sex tapes with Jin.
it's because he's only had gay sex prior to discovering My Little Pony.
He's only had gay sex, period. Doing it with a plushie doesn't count.
Has Twilight always been Jin's favorite character, or did his obsession with her really blossom when he started hearing her voice come from her plush? I mean it's likely since he already had a plush of her, but maybe he had more and got rid of the others once things got "serious" with twilight.
This shit is suprisingly facinating to think about. Or maybe my life has truly become so uneventful that pondering on whether a chubby, mentally unstable man has always had a preference for the the character he hallucinates about, or it was just randomly chosen by his psyche is fun for me.
He started hearing her voice because he was obsessed with her and filled his room with her image. When you're surrounded in nothing but that for weeks, even months, shit can become weird. I mean, weirder than it would be, covering your room floor to ceiling, wall to wall in cartoon pony merchandise. And, when you're reeeeeally depressed, your mind will make shit up to comfort you. In Jin's case, it was a projection of Twilight onto his cuddle toy. So... in other words, he's more broken now than ever before.
At least, that's my hypothesis. In answer to your question, he was obsessed with her first and that developed into psychosis... if I remember correctly.
I still wonder how he copes with people around him giving him weird looks and asking him why he's carrying a plush doll around. What kind of mental gymnastics does he use to keep his delusion plausible?
It never was plausible. Delusions don't have to be based in reality, remember - he believes it because he wants to believe it. If he does attempt to explain his reasons, though, which you can find examples of out on the web, it's very evident that his sense of reasoning is incorrigibly skewed. Check the comments of those derpibooru images with him tagged in (linked not long ago in this thread) it to see what I mean, he's probably commented on quite a few of them.