Stiles has never had anyone want to study him the way Derek does. He goes to class and on occasion, sticks mildly interesting things under microscopes, but he never thought he'd be the one picked apart, broken down to different sections to be examined and memorised as if there'll be a test later on that Derek is determined to pass. Before Derek, Stiles thought that he was merely mildly interesting, too, but then Derek began to read him and learn him. There isn't a scar that Derek doesn't know the story of or a freckle left hidden.

It's kind of terrifying because Stiles has never wanted anyone to know him that way. Not even Lydia. He's wanted her hands to touch every inch of his body, sure, but Derek doesn't just touch, he explores like it's the greatest adventure he's ever had, researches like he's going to write an entire book just about Stiles. When they're lying together, his fingertips climb his hips like tiny mountains, dip into the valley of his lower back, traverse the bone dry river of his spine. There isn't an inch of skin that Derek doesn't know and hasn't indexed in his mind.

He knows the spots to touch that will give Stiles goosebumps, goosebumps that he brushes his lips across like he's learning to read Braille. He knows that if he kisses just behind his ears, Stiles will shiver. He knows that if he trails his mouth along his collarbones, Stiles will sigh. Stiles is a puzzle to which only Derek holds the pieces, a question to which only Derek knows the answer. It is frightening and altogether satisfying, a brand new experience that Stiles is only just learning to adapt to.

It surprised him at first that Derek could be so gentle. Derek was always quiet, dark, suppressed burning rage with little flecks of joy here and there, an amused smirk or a half laugh. But with Stiles, Derek is all silent admiration, like Stiles is without question the most perfect thing he can imagine and if he talks too loud or touches too roughly, he'll turn to smoke in his hands. And he just can't have that. "I don't know what I'd do without you," he'd said three nights before now, and it had cut off a silly remark that Stiles had been about to make, choked it off in his throat and he'd just stared at Derek with amazement.

Like he's doing now. He's shocked that Derek has allowed him this far, allowed himself to be the subject of Stiles' rapture for once. And Stiles is completely overwhelmed. Derek is a wealth of hard muscle and smooth skin, and Stiles' hands are trailing down his chest, soft as feathers so that Derek huffs a laugh, turns his face away to hide it in the pillow. Stiles reaches out to grab his chin, turns his head back, runs a thumb over his bottom lip.

"You should do that more," he says simply, and then he moves in, lies prone on top of Derek so that they're nose to nose, eyelashes brushing eyelashes, a tiny press of lips to lips. Stiles tangles one of his hands in Derek's hair, lets the fingers of the other slip between his. He buries his face in Derek's neck, presses his lips there, feels his pulse beat steady underneath his mouth as he sucks a bruise to the surface. Derek sighs, lets out the closest thing to a whimper that Stiles thinks he'll ever hear, and twists their legs up together.

Stiles remembers before all this happened, how his feelings for Derek hit him like a train, how they welled up inside and bubbled just under his skin, Stiles daring the dam to break all the while. And when it broke, it didn't just fall to pieces, it burst into them, until all he could think about was the way Derek replaced old aches with new, more pleasant ones unique to him. The way he filled Stiles' heart until it too was ready to break open with a rush of happiness that Stiles hadn't quite felt since before his mom died.

All that they are is built upon the way Stiles genuinely loves Derek and the way Derek loves him unconditionally in return. But for Stiles, it is far more about the way Derek loves him, because that, more than anything, is still a sharp, cutting shock. Stiles had begun to believe that he was attractive to approximately zero percent of the human population, but then, that feeling was dependent on the way Lydia never really returned his feelings. So for someone that Stiles has a neverending well of feelings for to actually L-O-V-E Stiles back… well, that borders on completely unimaginable. And just like the way that Derek studies him, he thinks he will be content to study Derek, too, and even if it takes an age, to know everything about him because Derek is the rarest wonder of his world.