Here's the thing: when Stiles doesn't get stuff, he asks questions until he does. This was a problem when he was a kid – many an elementary school teacher fondly (or not-so-fondly) remembers Stiles as that year's “But why?” child – because there was so much he just didn't know. And god knows it ticks his dad off sometimes, when he realizes too late that his questions have gone just a little too far. Now that he's learned to google, he doesn't have to ask people so much about things.
But when he tries to google this stuff, about ninety percent of it is porn, which makes him find everything non-porn highly suspect. So... he asks.
“Do gay guys find me attractive?”
Maybe Scott isn't the best person to ask that particular question, but Stiles has a very small, very select number of people available for question answering, and he'll take what he can get. If Scott would ever answer him, anyway.
He tries going to a more accurate source: Danny. And yeah, he knows enough about statistics to know that asking one guy isn't gonna give him a real answer, but still. He wants to know.
He doesn't get how it works for people in romantic comedies. They just stare at each other for awhile and then, suddenly... kissing. Which is a weird thing, in and of itself, kissing. Stiles doesn't get that either. He'd tried making out with his pillow once, to see if it was something you had to do with a person to get the same effect or what, and just ended up with a giant splotch of drool on his pillow and a dry, cottony feeling in his mouth. Not very satisfying, or stimulating.
But getting back to the point.
Stiles doesn't get how people know these things. He's read that it's just observation of, like, blushing cheeks and pupils dilating and stuff, but that kind of thing is really hard to judge, even on people with pale enough skin to see a blush on. And touching you a lot, averting their eyes, what? How do you know they aren't just a really tactile person? Or that they didn't just want to look at something else right when you started looking at them? It's all really confusing. And since it's not something people are able to explain to him, or he'd have just read a romantic novel or two (or... six... look, he needed answers and was running out of options!) and been done with it, he has to find something to observe. But he doesn't know who to observe, or for what.
Hence his questions.
He almost gets his hopes up when Scott mentions being able to smell jealousy – if jealousy has a smell, maybe so does attraction. Maybe this is something he can figure out after all. He doesn't have Scott's super sniffer or anything, but he's got a decent nose on him. And if not, at least Scott can tell him who to look to for clues.
He asks if Lydia smells attracted to him because he thinks of everyone she's the person he'd most want to be attracted to him. There's always been something about Lydia: the shine of her hair, the authority in her voice, the smile she has when she's made somebody cry, the way she's always secretly working five chapters ahead in any given math class... it all draws him to her. She catches his eye, and he can't look away, doesn't want to. And he wants her to be drawn to him like that. That's pretty much what attraction is, right? Right.
But then Scott says no, sorry, and then Stiles doesn't feel like he can bring the question back around to general desire without making it weird, so he gives up on that lead. For the moment.
And then his general investigation into this “how to tell if people are attracted to you” business gets pushed back a few weeks due to, you know, werewolf serial killers.
By the time he can think about the question again, he has a decent idea how people of both genders show they're attracted. He's gotten a near lapful of Lydia, been invited (very threateningly) to take an eyeful of Erica's... assets, and been in a gay bar with Scott, who is apparently very attractive to gay guys. He gets how people do it, now.
So why isn't he affected by it?
He'd figured that's how it worked: once you knew somebody was into you, or you at least knew what they looked like when they were into someone, that “urge to scratch” feeling you get with morning wood would come up (heh) when you looked at them. Or thought about them, whatever.
But it didn't. Doesn't. He can remember that time Lydia practically crawled on top of him, ignoring that she was stoned out of her mind and thought he was Jackson, know that she was coming on to him, and... nothing. Well, nothing new. He's still drawn to her like a flower towards the sun, still thinks she's the most gorgeous, intelligent person he's ever seen, but there's no... physical side to it. No parts twitching or swelling, no heat in his stomach or face he can't attribute to pure nerves. No sudden urge to stick his things into her things. Nothing.
Once again, he doesn't get it. He was promised a reaction, a physical... thing that would happen when he saw someone he was attracted to. And he has to be attracted to Lydia, that has to be what this is.
So why is there nothing?
It's not like he's broken or anything; he jerks one out in the morning if he's got time, since his dick's already up and at 'em. And it feels good, scratching the metaphoric itch. It makes his brain go quiet for a minute, distracted by all the twitching muscles. Sometimes, if he really needs to be distracted from his thoughts, he'll jerk off more than once in a day. It's nice.
Sure, maybe it's not the be-all end-all locker room talk makes it out to be, but he figures that's 'cause it's just his hand. Like how you can't really tickle yourself, masturbation doesn't feel as good as sex. The way Scott looks when he's thinking about Allison sometimes, Stiles figures he's gotta be right about that. He wants to know what that's like. He wants to feel that.
If it's as good as Scott's expression suggests, he wants to feel that as many times as possible, in as many possible ways.
But he's not sure how. Which isn't to say that he doesn't know how the actual mechanics of sex work. He does. They just don't seem... very sexy, he guesses. Not that he thinks about what makes things sexy all that often; when he jerks off it's a physical thing, just enjoying the sensation. When he thinks about it, that doesn't seem normal.
He's doing this attraction thing all wrong, isn't he?
After a while of getting no satisfactory answer to this latest question (delayed by further werewolf-tangential serial killing), Stiles starts wondering if maybe he is broken. Not his body, but maybe his mind? Because his body is functional. And the way she draws him to her, he's sure his heart belongs to Lydia as completely as humanly possible. So it seems like the only reason his body wouldn't belong to her too is if something's wrong in the connection between heart and body. And that's the mind.
But then, while he's googling depressing variations of “can you love somebody without wanting sex with them or is my brain just having a major malfunction?” he finds this random forum Q&A where somebody refers to sexual and romantic attraction as two separate things, things that some people don't experience at all. Something perks up in the back of Stiles' head, crying “yes! yes, that's me!” and he reads on, follows the link at the bottom of the post to a site called AVEN, and suddenly has a word for what this is. For what he is.
And it's not “broken,” or “wrong,” or anything like that.
It's a lot easier to be around Lydia after that. Sure, he might not ever get her to love him, but love's a different thing for her than it is for him. She gets something out of her relationship with Jackson that he wouldn't be able to give her, and honestly? Just having her attention, her tentative friendship, is pretty damn close to everything it turns out Stiles wants, so he's not complaining.
Why would he be? He finally gets it.
(Now, if only that werewolf-related serial killing would stop for good, he could take the time to figure out if this romantic attraction thing goes both ways, or if he's only drawn to girls.)