Scott has abandoned him.
This is not even an 'Allison in peril' situation, which Stiles was forced to give Scott grudging, special dispensation to abandon him for. No, he's been abandoned when Allison is, as far as he knows, not in any sort of peril at all. She's probably not even slightly bruised. He's been abandoned for an Allison who is most likely in perfect mint condition. Well not mint condition, she's almost certainly been unwrapped at the very least.
Also, Stiles may be a little bit drunk. He may be a lot drunk. He's drunk and in the woods, and he's been abandoned. This is like the pre-credits sequence of every horror movie ever made, he's probably going to be eaten before the main character is even introduced. He doesn't even merit a space in the opening credits. He's there purely to be killed as graphically as possible, to provide tension to all the night time woodland encounters that come after. He'll be the gruesome corpse teenagers talk about, and come looking for.
"What are you doing?" Derek's a huge, dark, blurry shape in the crunchy leaves to his left, and Stiles never even heard him get to the crunchy leaves to his left, which proves his stealthy woodland instincts are probably shot to shit. The only reason Stiles didn't jump a mile is that jumping is currently beyond him. He probably could have flailed in surprise - though the moment's almost certainly gone.
Derek's frowning and looking generally disapproving and murderous. He could probably literally smell that Stiles was drunk a mile away.
"I'm the pre-credits sequence," Stiles tells him. "It's very sad. I'm better than that, Derek."
Derek doesn't have any opinion at all. He has scowls, there are no opinions, only scowls. The scowls are directed at him, all the time, it's very unfair.
"You shouldn't be out here," Derek says finally. Stiles thinks he says that every time he comes across Stiles in the woods. He should really have learned by now that it doesn't do any good. There will probably never be a good reason, or time to be in the woods. But Stiles will be here anyway, possibly with Scott, possibly also in terrible peril. Derek is like the 'don't go up to the castle,' guy. No one listens to him either. They keep going up to the castle - woods. He's lost track of where he was going with this?
"They never listen to you," Stiles says plaintively. "And I'm the pre-credits sequence - oh, but now you're here, which means you're the main character. Which would technically make me the comic relief, so there's a possibility that I won't die after all." That was reassuring. "Unless you're the monster, in which case - it still ends badly for me. Why would you do that though? After everything we've been through?"
Derek's staring at him like he has no idea what he's talking about. Stiles likes that face a little better, it's not cross so much as confused, a pained sort of confused. Like it hurts Derek to feel anything but angry, which must be exhausting.
Derek sighs and takes two steps forward, and there's a certain amount of levering and swaying, and Stiles does briefly end up kind of hugging him, but it's mostly an accident.
"He left," Stiles says, because using the word 'abandoned' is sad and whiny. He still sounds kind of sad and whiny anyway. Sad and whiny in two words is definitely a low point of the night.
Derek looks briefly cross again, and then he's holding Stiles's arm and looking like he really doesn't want to do whatever he's about to do. Which Stiles is pretty sure is haul his drunken ass home, in some sort of embarrassing and overly dramatic way.
No, absolutely not.
Stiles shakes him off. It takes a few shakes, and he mostly loses his jacket doing it. He's not very coordinated.
"Do not carry me, I'm capable of walking on my own."
It turns out, to Stiles's great distress and intense irritation, that he is in fact not capable of walking on his own. Because it quickly becomes apparent that his being on the ground to his actually physically walking, ratio is heavily biased towards the ground so far. It's very annoying. He's never getting home like this.
Derek's boots seem to be mocking him, and when Stiles manages to shove his way out of the leaves Derek's knees are mocking him too.
"Why would you do that, don't you know how hard I'm trying here? We can't all be werewolves." They couldn't all be werewolves because then there'd be no normal people to be...he thinks about it for a minute...firefighters and jet pilots and astronauts. Oh my God, there should be werewolf astronauts! But then they'd probably claw their way through the suits and die in the vacuum of space, and that would be really freakin' tragic and horrible.
There are hands on him and Stiles is upright again, and this time he's determined to walk like the upright species he belongs to - which isn't werewolf - no matter how long it takes. But Derek is apparently unwilling to be patient while Stiles convinces his body to do as it's told. No, Derek solves the problem of locomotion by looping an arm under and around him and just hoisting him over his shoulder. Which is unexpected, and kind of hilarious and maybe a little humiliating. But then it's mostly just dizzy, because he's nearly upside down, and he has a loose grip on Derek's jeans, or possibly his ass, and they're moving. There's so much moving going on it's not even funny.
It's a strange jolting, swaying movement and Derek may be all attractively muscled and stupidly warm, but he's really not all that comfortable. The jolting and swaying is not a smooth motion.
"Oh my God." Stiles says, because he's not sure if his body likes this...he's pretty sure that it doesn't. "You are so uncomfortable."
The swaying turns into swirling, a horrible ebb and flow that doesn't know which way is up, so just flows wherever it likes. It should not be allowed to flow wherever it likes. His stomach and his head and his legs do not like this at all, and he's going to be very sick in a minute. He buries both hands in the back of Derek's jacket and shakes it.
"I'm going to be sick on you," Stiles tells him, because it's always polite to warn someone about something like that.
He's expecting to be dropped, immediately. He even braces himself for the short fall, and the unpleasant stop when he hits the dirt. And he's pretty sure it wouldn't even hurt, because pain has this way of time-traveling into the future when you're drunk. But Derek doesn't drop him, he very carefully sets him down and steers him over to a log. Then he makes him sit on it. For Derek this is like a full conversation. The world is still sort of spinning, but if Stiles leans forward he'll end up with his face in Derek's crotch, and that's a sort of awkwardness that he's both too drunk for, and so very much not drunk enough for. That is not an appropriate way to make your interest known.
"Why does it feel like I'm still moving?" Stiles is really annoyed about that, because he's up the right way and no longer swaying and this makes no sense. "This makes no sense. I'm no longer moving, why does my brain think I'm moving?" His stomach still doesn't approve of the imaginary moving.
Derek sighs, loudly, and grumbles something which Stiles is sure is very rude and uncomplimentary. But then there's a hand on the back of his neck, very slowly rubbing where it's kind of damp and sweaty and easing him forward a little bit, and that's so much better. It's actually sort of floaty, and he no longer feels in danger of utterly humiliating himself. In fact he feels like he couldn't possibly humiliate himself if he tried, which is a new and interesting feeling. He should take advantage of his emotional invulnerability while it lasts.
"We should go out for milkshakes some time, because you really are insanely attractive."
Derek's hand stops moving on his neck. It just sort of clamps into stillness. Stiles frowns at him because he was actually enjoying that quite a lot. Derek's giving him a very strange look, which is nothing like any of his usual looks. It's very much a new look and Stiles sort of wants to touch it, but he's using his elbows to hold himself up and his hands are kind of attached to them...eventually.
"In a manly way," Stiles adds, because that's probably important, he doesn't want to offend him. "And you smell amazing, and you have this heroic saving thing - ok, we have like a competitive, mutual life-saving thing going on. There's a lot of saving, which is very confusing. But I like to think we're working up to the part where we can hug and have subtext-y moments of conflict, and we can stand too close and you can breathe at me in that sexy way that's supposed to scare me but mostly just makes me want to drop to my knees and - Anyway, I thought maybe we could pretend we were there already. I'll even let you throw me into some stuff, if you like, a little bit, so it's not too weird. I know you can't help it, and I like you, so I'll let you do it, if it makes you feel better. So, yes, milkshakes."
There's a long moment of silence which doesn't tell Stiles anything at all. But then Derek's hand very slowly starts moving again, and that really is amazingly nice.
"You should say yes," Stiles tells him. "I probably won't remember this tomorrow and I think it would be very awesome for my self-confidence if you said yes right now."
Derek gives him this look, sort of intense underneath his eyebrows. Looking like a man who's never been asked out for milkshakes before - and it occurs to Stiles that 'milkshakes' don't really sound very mature and date-like (unless you come from the nineteen-fifties,) and it's probably going to lose him points. But Stiles pretends that Derek's giving serious thought to his proposal - rather than thinking up a nice, soft, relatively safe place where he can dump his body. The emotional invulnerability is wearing off, and he suspects this may be horrible.
"Fine," Derek says at last. It sounds quiet, and not angry at all.
That takes a moment to sink in, but when it does - when it does Stiles is still not entirely sure it has. Because - wow.
This is absolutely worth it for the hour he's going to remember it for.