Warning: Explicit sex.

Charles takes Erik's fumbled explanation—that, yes, Charles is not entirely alone in his inappropriate attraction (which is actually really only inappropriate from Erik's side), but they can't act on it right now, they're going to have to wait until Charles turns eighteen—with relative equanimity, which should really tip Erik off immediately that something is not right.

As it is, though, Erik's just relieved enough to not have his resolve tested that he doesn't examine Charles's acquiescence too closely; this is why he is completely blindsided at the evolution of Charles's carefully calculated war of seduction, apparently designed to drive Erik completely out of his mind.

Charles takes to wearing clothes that Erik suspects have come from the early depths of his closet, because they all fit too tightly, too short, too not enough. Charles stretches up to close a window, and Erik gets lost in the pale band of his lower back that's practically begging for Erik's touch.

Erik is twenty-three, really, he knows what to do with his cock and everything, he's not going to make a fool of himself and crumble over Charles's (absurdly endearing and startlingly effective) lack of subtlety in his seduction attempts.

(That is possibly the worst lie Erik has ever told himself.)

Charles entirely drops the concept of personal space when he's with Erik, as well as finding ways to invite himself and Raven over to Erik's place, before Raven "suddenly remembers" she has other plans that evening.

"Raven has friends to go see today," Charles says the first time this happens, cheerfully, innocently. "We can watch a movie or something at your place, can't we? Just the two of us?"

"I do have friends to go see," Raven agrees blandly, when Erik corners her for interrogation later. "I have some unidentified friends to go see, and later today I will be in possession of Charles's Harry Potter boxed set. There's no correlation between these two events, of course."

"Of course," Erik says.

"No, but really," Raven says, "if I weren't shamelessly susceptible to bribery, you understand that I'd be cockblocking the fuck out of you, right?"

"I'm glad Charles's virtue rates so highly with you," Erik says flatly.

"Well, plus, I figure you're kind of cockblocking enough for the both of us," Raven says wickedly.

"I just want to—do this right," Erik says, knows that he's flushing a little at how inept he sounds, how ridiculous, as if this is the 1920s and he's asking for Charles's hand; if nothing else, Erik is fully aware of ridiculous this is getting, because the only person who seems to have any problem with this is him.

Raven visibly melts at that, but it doesn't exactly help Erik with his problem, which is that Charles's persistence is unbelievable. Erik has never jerked off so much in his life.

In his bed, in the shower, on the couch sometimes, thinking about how Charles drives over to Erik's place after class, and inches closer on that very same couch when they sit together until he's pressed up against Erik's side, fingers falling oh-so-accidentally onto Erik's thigh; in Erik's mind, it's okay to picture pushing Charles down onto that couch, sucking his cock as greedily as he wants to, watching him go pink and breathless with want, and afterward, when Erik's fingers are sticky and his heart is pounding, he realizes he'll never be able to sit on that couch again without going hard. Erik's whole apartment has become a minefield of fantasies, that wall he's imagined pressing Charles against and kissing him senseless, the kitchen counter that is the perfect height for him to lift Charles onto so Charles can put his legs around Erik. Erik is in a permanent state of distraction over Charles.

Charles is both brimming with confidence and sometimes unsure, the way he backs Erik against a wall and goes up on his toes and kisses him firmly, telling Erik the first time he does so, "Don't be ridiculous, Erik, it's only kissing"; the way he blushes, eyes going wide, when he sees Erik watching him and Charles clearly hasn't even meant to catch Erik's eye, and the soft pink bow of his mouth parting open makes Erik grit his teeth and wrench his gaze away.

Erik is, quite honestly, in over his head here: he's blunt, and he's been called aloof, and he doesn't want much to do with most people; he's never learned how to be careful with someone, and he has to be careful with Charles, no matter how little Charles wants it—not because he's young, but because he's Charles, and he is important.

Erik has no idea what he's doing here, and yet, for all that, he's never been this happy.

He lets Charles surprise him in hallways and push him against things and kiss him, because Charles so clearly wants it, and Erik is only human, and there is nothing like the feeling of Charles tucking himself into Erik's body like he's trying to climb inside him; Charles has sly, wandering hands, and Erik laughs, low, against his mouth and traps one by the wrist and watches Charles pout at him.

Charles is shameless and beautiful, inexperienced but not naïve, assertive and a little uncertain, and Erik would take care of him so well, find out what he likes, everything he's never thought of, everything he'd love, he'd make him so happy he'd never want to go anywhere else.

It gets harder and harder to pull away from Charles, and Charles looks more and more frustrated when he does, and Erik doesn't know how to explain how important it is that Erik do this right, that Erik be good enough—

"Erik, why can't we just—" Charles says from where he's backed Erik against a wall, breaking off in helpless frustration, hands fisted in Erik's shirt.

Erik could give in so easily, and no one would blame him. Charles clearly thinks he's being nothing less than pig-headed and has told him so in no uncertain terms.

Intellectually, Erik knows there is very little difference between seventeen-and-six-months and eighteen; there isn't some magic threshold Charles will pass on his birthday that will make him more ready to have sex with Erik. Erik knows that what's holding him back is the most irrational kind of fear: his parents are gone, have been gone for years, and Raven and Charles mean everything to him, and if he fucks this up in any way, that will be it. He's thought of every reason why this thing with Charles is a phenomenally bad idea, has let Charles shoot each one down; but some part of him still worries that Charles might change his mind, that if Erik is pushing him into this—however unknowingly—and Charles wants out of it later, it will ruin this complicated thing that Erik holds so dear. Erik has been telling himself every day, like something to hold onto, that if he waits just a little while longer, then he's passed the test and he can make this work.

It's unfair toward Charles to project his own insecurities onto him, because in his head Erik knows, he knows that Charles is not flighty or fickle, he doesn't make choices lightly, and in this he's probably emotionally better-equipped than Erik. Erik isn't waiting for Charles to turn eighteen because Charles isn't ready.

He's waiting because he isn't.

Erik doesn't know how much of this he's showing on his face, but whatever Charles sees has him uttering a soft "Oh," of understanding, before he puts a hand against Erik's cheek and says quietly, "Okay. I'll stop pushing."

He's about to pull away from where he's pressed up against Erik's front, but Erik manages to clear his constricted throat and gather himself by that point, and grabs Charles by the hips, fingers tightening in place.

"It's not you, it's me," Erik says after a split-second of debate, very earnestly, and watches Charles's face do something complicated that means he can't decide whether to laugh or scowl or just roll his eyes really hard. Because Charles probably hears the honesty in the facetious comment, he settles for poking Erik in the side; and when Erik says oh-so-casually, apology and a plea both, "I—the ambushes can stay," Charles grins, open and bright, and kisses Erik with all the sweet presumption of someone who's been given explicit permission to do just that.

True to his word, Charles does not push for more than those kisses that leave him swollen-mouthed and mussed and endlessly tempting; but Erik is under no illusion, in the months that follow, that Charles is doing anything but biding his time.

That's all right, though. Pulling away from Charles gets no easier for Erik each time he does it.

Charles isn't the only one waiting.

Charles's birthday, when it finally comes, is sacred territory for Raven and Charles, with years of tradition setting their plans, but Erik gets the night before with him.

"Ask him where he wants to go for dinner or something, and then I guess you can take him home with you," Raven tells him, "and I want no details on anything else that might happen afterward. None."

Erik rolls his eyes. "Raven, I'm not going to—"

"No details!" Raven says again agitatedly, looking as if she's inches away from throwing her hands over her ears, and hurries off before Erik can tell her that, really, he's not about to jump on Charles the minute he turns eighteen. He wants it at least a little more well-planned than that.

"It's my birthday tomorrow," Charles announces when he sees Erik later, as if Erik had no idea. "I seem to recall it being somewhat important—how old am I going to be again?"

"You're a terrible brat," Erik says calmly, "so I really couldn't say."

"Eighteen, that's right," Charles continues, ignoring Erik's words, smile twitching at his lips. "Now, what is it that happens when I turn eighteen…"

"You get to vote?" Erik suggests. "I know how excited you get about the workings of our government."

Charles, who has started investigating the curve of Erik's cheekbone with his mouth, nips Erik's ear in response. "Are you going to be this awful to me on my birthday?" he asks, breath warm on Erik's skin.

"I suppose you'll have to wait and find out," Erik says, turning his head a little to catch Charles's mouth in a kiss that Charles gives in to eagerly, like he always does with everything Erik gives him.

"I can't go to sleep in my clothes," Charles says casually. "Can I borrow something?"

Dinner had passed by in a blur, and then Erik found himself asking Charles to come home with him almost without meaning to—except that he did mean it, really, because he might not have any plans for debauchery tonight, but he's never going to turn down more time with Charles. And so he took Charles home, watched a movie he bets neither of them remembers with Charles tucking his feet under Erik's legs, scrounged up some dessert while Charles laughed at the sad state of his fridge, and now Charles is standing in front of him and trying to break Erik's brain.

Erik is slightly frozen, trapped in the image of Charles wearing his shirt—too large, baring the curve of his shoulder, skimming his thighs—and then he catches the sly curve of Charles's mouth a minute later.

"Menace," Erik says in a tone that is supposed to come out fond, but emerges suffused with thick, rolling heat instead; Charles takes a sharp breath in response, and it's all Erik can do to break away from the hold of his darkening eyes and grab Charles something to wear to bed.

Charles looks as unfairly tempting in Erik's clothes as Erik imagined he would. Erik wonders, for a moment, if he will have the strength to put Charles in Erik's bed and take the couch himself, as he has planned; Charles solves that problem for him, sets his chin and says firmly, "It's my birthday, Erik. You're sleeping next to me."

"Not your birthday yet," Erik points out, but he's already going for the lights, watching Charles slide beneath the sheets and curl toward the side of the bed, an open space left for Erik to take.

"Close enough," Charles says, voice sleepy and a little smug and, perhaps, the slightest bit uncertain. "You don't have much longer to run away."

Erik gets into bed and finds Charles in the dark, drags him in close until they're touching arms-bellies-hips-legs, Charles's toes tickling Erik's shin and his head on Erik's shoulder, and Erik whispers in his ear, "Where would I go?" and means How could I go without you?.

"Nowhere," Charles says resolutely, even as he sinks into sleep, and Erik holds Charles as close as he can be without crawling inside him, and slowly falls under.

Erik wakes with a start to find Charles straddling his waist, leaning forward with his hands braced on Erik's chest, face inches from Erik's. Erik blinks, eyes flicking to the clock by his bed. It's two in the morning.

"It's my birthday," Charles says pointedly. "Now, are you out of excuses, or are there a few more you'd like to get out the way before you fuck me?"

And Erik—Erik is done. It's not like he hadn't known this was coming, really. And it's about time he let Charles upend his plans for some of Charles's own.

In one swift move, Erik flips them over and watches surprise light Charles's eyes when his back hits the mattress, cups Charles's neck and feels his pulse hammering under his fingers.

"I think I'm good," Erik says, grinning a little, fingers sliding smoothly down Charles's throat to dip under the collar of his t-shirt. Or, well, Erik's t-shirt, really; and at that thought, Erik tugs the shirt down a little further until he can see a flash of collarbone, thumbs the curve of it when he does.

"Good. I won't say anything about how long it took you to get there, then," Charles says in an attempt at tartness, but it wavers a little when Erik reaches out to flick on his bedside lamp—the light is a soft golden glow, not too harsh, but enough to see everything clearly. Charles blinks a little, hair in disarray, and he's breathing fast and clearly wants Erik's hands on him, but there's also a flush spilling over his skin, and he looks a little nervous, and Erik remembers again that Charles has never done this before.

"You'll tell me if I do anything you don't like," Erik says, tipping Charles's chin up until their eyes lock, and it's a plea and half-order at the same time. Erik really, really does not want to fuck this up. He refuses to.

"You doing something might be a start," Charles retorts, squirming a little, and Erik huffs out a laugh at the petulance in his voice, bends down and kisses Charles's half-open mouth softly, feels the sweet give of his lips as Charles puts his hands on either side of Erik's face for leverage.

Erik is still harboring the very slight worry that he might not be good enough or careful enough and what if he ruins sex for Charles completely, and—

And then he puts his hand under Charles's shirt, low on his stomach, thumb stroking, and Charles shivers and goes hot-eyed, melting into the bed, and Erik feels abruptly both silly and relieved. Charles is eighteen—Erik remembers eighteen, when all he needed was the right kind of look to go blindingly hard. There are really very few ways in which Erik can fuck this up.

Erik rucks Charles's shirt up and skims his hands along Charles's sides, satin skin over the dip and rise of bones, thumbs one of Charles's nipples and watches him shudder in place; Charles swallows and says in a thin, panting voice, "Please," and oh—

"Sorry," Erik says, because no matter how sweetly it hooks into him, he hadn't meant to make Charles beg; it's only that there's so much he wants and so much he wants Charles to feel, and he'd like to do it all at once.

But eighteen, eighteen, he says to himself, and Charles has to be nearly out of his mind by this point. Besides, it's not as if he'll have a problem continuing afterward.

When Erik curls his hand around Charles's cock, Charles makes a strangled noise high in his throat, eyes slamming shut; Erik watches the delicate inky shadows of his eyelashes, the flush riding his cheeks, resists the urge to kiss Charles's panting mouth while he jerks him off.

A second later, he realizes there's no need to resist anything.

Erik leans down and kisses Charles's lower lip, tugs it a little with his teeth. Charles thrusts into Erik's hand, the slick-quick noise of it loud in the stillness of the room; his eyes are open now and fixed on Erik, vividly blue, almost shocked. It's no wonder, though, Erik knows it's different when you're being touched by someone else for the first time—

And Erik mentally rewinds that sentence, goes over it again: Charles has never been touched by anyone else before.

Erik swallows a noise that would be thoroughly embarrassing if it actually emerged, kisses the underside of Charles's jaw, then draws back and says wonderingly, "Charles, Charles if you even knew how you looked—"

Charles sinks his teeth into his own lower lip when he comes, until Erik tugs it free with his thumb; now Erik can hear the shaky, breathless sounds Charles can't hold back, the aborted attempts at Erik's name while Erik works him through his orgasm, cock striping his shirt with come. Charles goes boneless on the bed when he's finished, swallows a few times like he's trying to speak but he can't quite make it.

Erik carelessly wipes his hand on the sheet and watches Charles touch two fingers to his shirt, looking a little satisfied, like he likes the idea of leaving himself all over something of Erik's.

Or maybe that's just Erik projecting.

And then Charles looks up and catches Erik's eye, says in a tone that's trying for exasperation but holds too much languid, bone-deep pleasure to ever reach that, "Would you please get your clothes off now?"

Erik laughs, the bared-teeth, unguarded laugh that Raven tells him makes him look like he's about to take a bite out of someone; but Charles's eyes flash with heat at the sight of it, so maybe he wouldn't exactly be opposed.

"Sorry, did you want me to stop in the middle to take my shirt off?" Erik asks mock-solicitously.

"It's not like I don't have hands," Charles says cheekily, wriggling eel-like out of his clothes and tossing them somewhere over the side of the bed.

"And was it the same?" Erik asks, voice a low rumble in his throat. "With my hand," he clarifies unnecessarily, and puts one of those hands on Charles's bare thigh, watches creamy white skin dimple under the broad span of his fingers.

"No," Charles breathes. "It wasn't."

Erik draws back and pulls his shirt over his head, feels Charles's eyes on him all the while. Charles stares up at him for a minute, until he says in a slightly strangled voice, "You're never allowed to wear a shirt again."

Erik grins, and says, "People at work might have a problem with that."

"No, I really don't think they would," Charles counters distractedly, and the look on his face has Erik kicking out of the rest of his clothing in record time; he lies back on the bed and tugs Charles over him until their positions are reversed, Charles straddling Erik's body, eyes wide.

For a brief moment, Charles looks like he doesn't know where to put his hands, until Erik says sincerely, "You can do whatever you like," and Charles makes a choking noise that sounds a little like a laugh, mutters something that Erik thinks might be, "—like you walked right out of my dreams—" and then apparently decides to take Erik at his word. He runs a thumb down the line of Erik's throat, closes both of his hands around Erik's biceps like he's taking the measure of them. The breath that Charles lets out in a whoosh assures Erik that he hasn't been found wanting.

Erik lets Charles explore at his leisure, hands fisted in the sheets to keep from moving Charles where he needs him, teeth gritted with the effort of holding back; he wants Charles to do whatever Charles wants. Charles is frowning in concentration, fingers careful but not shy, and when he slides down the bed after a length of time and bends his head to trace the line of Erik's hipbone with his tongue, Erik couldn't stop the groan from leaving his lips if someone had a gun to his head.

Charles looks up at that, mouth dropping half-open at whatever he sees in Erik's face, and his color rises even as he swallows and says, "You can touch me too, you know."

Erik doesn't make him ask twice. He wants to touch Charles everywhere, has thought about it for months, but the first thing he wants now is to sink his fingers into Charles's hair and tug, gently, messing him up a little—so he does.

Charles cries out, a high, surprised noise; Erik's fingers pause and Charles demands peremptorily, "Again," and Erik drags his fingertips over Charles's scalp once more, pressing at the base of his neck, pulling on his hair a little harder this time. Charles drops his forehead against Erik's stomach, breath panting warmly against Erik's skin. The back of his neck is flushed warmly, and Erik can't resist the urge to run his fingers there too.

Charles rears up and says, "Oh, christ, Erik can I—" and he wraps his hand around Erik's cock, mouth falling half-open and head tipping forward as if of its own accord, and he's panting like he wants it so badly; Erik digs his nails into his own thigh to distract himself a little before he embarrasses himself completely.

"Yes," Erik says, and he doesn't even recognize the sound of his own voice, as dark and gritty as it is. "Yes, Charles, please—"

Charles's mouth slides over the head of Erik's cock, and Erik almost bites his own tongue off; it's shockingly good, for all that Charles has barely done anything yet, wet heat and the hesitant slide of Charles's tongue, the tight curl of his fingers. Charles is a little clumsy, but he's achingly careful, and he keeps trying to get more of Erik's cock in his mouth like he's greedy for it, like he loves it. Erik touches Charles's cheek, the circle of his wet, pink mouth, and notes distantly that his hands are unsteady.

"Charles, do you—" Erik starts, and his teeth click forcefully together as he cuts himself off midsentence, because what wants to come out of his mouth is Charles, do you want me to fuck you, and he's not going to be the one to bring it up first, not before Charles asks. It won't happen a minute before Charles is ready.

But Charles lifts his head away, and with his usual (often inconvenient) burst of perceptiveness, he hears the words that Erik hasn't let slip. "Yes," he says, eyes widening, hand tightening on Erik's leg, and scrambles up the bed until they're eye-to-eye. "I want you to."

Erik doesn't ask him if he's sure; Charles lies back on the bed, looking a little self-conscious, but his cock is hard against his stomach and he spreads his legs open with nothing less than eagerness when Erik goes for the lube.

Erik slicks his fingers and sinks one into Charles slowly, carefully; Charles's breath catches audibly, and his eyes flit from Erik's face to his moving hand to the rest of Erik's body that is taut with concentration, like Charles can't decide where he wants to look. Erik continues at this slow, tortuous pace, until Charles wriggles a little and says helpfully, "I've done this with my fingers before, you don't need to be so careful."

Erik freezes in place when he parses those words; jesus, like he needed the extra motivation. Charles must see the wave of blind lust that's turned off Erik's brain, because he flushes even pinker, looks more than a little pleased with himself. Erik thinks about Charles in bed at night, pushing his fingers inside himself and biting his lip to keep himself quiet, imagining it's Erik instead, perhaps; and Erik bites back a fervent curse, kisses the inside of Charles's thigh to watch his stomach tense in response, and stretches Charles open with another finger.

He fucks Charles with just his fingers for a while, half for thoroughness, half for the pleasure of watching Charles writhe and fall apart beautifully, moaning like he's been drugged, a wet sound that spills from his throat and kicks Erik low in his gut. Charles finally breaks, throwing a wrist over his eyes and snapping, "Erik, will you just fuck me." He's pink down to his chest, still covering his face, and Erik could happily listen to him asking for it a hundred times more, sweet mouth saying fuck like he's holding the word on his tongue; but they're both dying for it, Charles nearly vibrating with need, and Erik could never deny him what he wants.

"Anything you want," Erik says, and it comes out rough and raw like he's swallowed sand; unsteady, honest. Charles takes his arm away from his face, hair mussed and sticking to his forehead in places, and his eyes, fixed on Erik's face, are the brightest blue Erik has ever seen.

Erik rolls on a condom and opens Charles up with his cock, a slow, inexorable push that has Erik panting for breath and Charles digging his fingers into Erik's tensed arms. The sound that escapes Charles's throat is steeped in something like relief, when Erik is as deep inside him as he can get; Charles shuts his eyes and says wetly, a ragged half-laugh in his voice, "You don't know how long I've been thinking about this."

"You'll tell me later," Erik says, and means it. He'll make Charles tell him sometime, all he's thought about, all that he's dreamed, all he's ever wanted, and then Erik will give it to him: everything.

Erik fucks Charles deep and slow, thorough, driving gasps out of Charles's throat, a full-out cry when he gets in at the right angle. Charles's nails bite into Erik's back every time Erik drives into him, tiny pinpricks of pain that fuel Erik's arousal, and there's sweat gleaming in the hollow of his throat; Erik can't resist the sight of it, bends down and licks the flushed skin there for the taste of salt and the feel of Charles's cry vibrating under his tongue, and Charles gasps out, "I can't—I need—" and fumbles for his own cock, dropping his hand away when Erik reaches for it instead.

Slick, hot weight in Erik's hand, and Charles barely lasts two strokes before he's coming between them, all over his own stomach and Erik's hand; he tightens around Erik's cock, body shaking, and with that and the choked sounds wrenched from his throat, the open-mouthed stunned look on his face, with how long Erik's been on the edge, he doesn't have it in him to last much more past that.

It's like being hit by a train when he comes, devastating and shattering, rearranging him from the inside out; he's dimly aware of Charles's hand slipping over his face and reaching around to cup the back of his neck, and when his breathing finally settles, Charles kisses him fiercely and steals the breath from his lungs all over again.

"Just think," Charles says after a while, after Erik has cleaned the both of them up and tucked the sheet around Charles's lower half so he doesn't get tempted to put his hands on him all over again, "we could have been doing that for months."

He looks smug, a little shy when Erik looks at him for too long, pleased and sated and debauched; and Erik sinks his fingers into Charles's hair, tugs at it to watch Charles squirm, and says with amusement and promise in his voice, "However will I make it up to you?"

"I'm sure I'll think of a few ways," Charles says, pulling Erik down on the bed so he can put his head on Erik's shoulder.

And with happiness like a warm stone in his chest and Charles tucked into his side, Erik buries his grin in Charles's hair and murmurs, "Happy birthday, Charles."