Title: Slow Burn
By: Eleanor Lavish
Pairing: Gil/Nick
Rating: NC-17
Summary: Gil, Nick, and volatile chemicals shouldn’t really mix… Takes place early in Season 1.

For the CSI Lyrical Twin Challenge:

When you dropped that little pin
Never thought what a mess it'd get you in
(The Who, Run Run Run)

*

"Shit!" Nick is pretty sure Grissom's tone of voice alone would be enough to get him moving away from the bubbling concoction in the garage, but the sudden stinging pain on his arm gets him moving even faster.

"Ow, oh, damn!" When he looks down, there's a tiny hole near the hem of his old A&M t-shirt.

A second later, Grissom's hand is tight around his wrist and he's being dragged through the living room to Grissom's bathroom. Grissom's shaking his hand out like he's been bitten and Nick's suddenly aware of a dozen tiny stinging spots on his own body.

"Take off your shirt."

Nick stares at his boss stupidly for a second. Grissom is already naked from the waist up and reaching into the stall to turn on the shower.

"Now, Nick!"

"What the hell..." but his words are lost in the fabric of the shirt as he pulls it up and over his head. Grissom is in the shower already, scrubbing hard at his arms with what smells like disinfectant soap. He reaches out long enough to tug Nick in with him-- jeans, shoes and all.

"Seems I mismeasured something back there." Grissom's face has relaxed a tiny bit and Nick's arms feel less like they're on fire once the soap hits them. "Wasn't really going for something with quite this acid level."

"Or that explodes." Nick smiles but keeps his eyes on his arms, even when Grissom laughs. They're covered in tiny red dots, like chicken pox. Grissom's standing incredibly close, the water running down his back like tiny rivers and Nick's whole body itches at the closeness. He clears his throat roughly before asking, "Are kids chemistry sets supposed to be able to do that?"

"Well, no. I kind of... brought some stuff from the lab."

That makes Nick look up, his eyes big, but he's already smiling. "You're insane."

"What? I didn't steal it. It was my stuff." Nick notices that Gil's arms have the same polka-dot pattern as his. The stinging is pretty much gone, but they keep scrubbing anyway until the water runs cool. The combination of the cool water and the warm heat in his stomach make Nick shiver involuntarily. Grissom turns the water off and looks at him with a half smile. "I think we're in the clear. If Cath asks tomorrow, it was a wild swarm of bees, alright?"

Nick laughs at that, running his hands through his wet hair. Grissom's slacks are sopping wet and heavy, sitting dangerously low on his hips. Nick looks down to see his jeans doing the same thing, and is fervently grateful to the bulky material for hiding what has become an obvious arousal. Grissom leaves him in the bathroom for a minute while he rummages for dry clothes for the both of them.

The second he's alone, Nick leans heavily on the sink and stares at himself in the mirror. Sure, Gris. Chemistry lesson. Sounds fun! And really, Nick would jump at any excuse to actually see Gil Grissom's house, to be alone with him. The last hour had been more fun—in that amazing Grissom science geek way-- than Nick would ever admit to his frat brothers. It had seemed an easy way to get closer to Grissom, to observe his boss in his natural habitat, to see him smile outside the lab. But this... this is way more than Nick bargained for. Crushing on the boss over a chem set was one thing; ending up half-naked in the shower with said crush was completely different. Nick takes a deep breath and wills his body to cool down and deal. Grissom hadn't stripped him and thrown him in the shower for a quickie. He'd done it to save them both from second-degree chemical burns. Not a sexy idea, really.

When Grissom opens the door with another wry smile and a pair of old sweats, Nick proudly smiles back without blushing.

"Here. Change into these and I'll throw everything else in the machine." Grissom is wearing sweats too, and an old Berkeley t-shirt. It's the most dressed down Nick has ever seen his boss, and he wonders as he changes at how much younger the clothes make him look.

When he pads barefoot out into the living room a minute later, Grissom is on the phone. He cups his hand over the receiver and asks pointedly, "Pepperoni good for you?"

"Yeah," Nick smiles as Gris finishes the pizza order. Inwardly he's caught between a cheer and a groan. He's clearly stuck at Grissom's house for another hour at least, and it's thrilling and not a little unnerving. The fact that Grissom's clothes are a bit too big on him doesn't help, and Nick plops down in a large chair to keep from hiking up his pants again. He finally takes a good look at the townhouse—not really sterile for all its black and metal accents. Too much clutter—academic journals, specimen jars, piles of personal paperwork. Nick smiles to himself. Looks a hell of a lot like his office.

"Beer?" Nick startles when Grissom appears at his elbow, open bottle in hand. He takes it gratefully and motions for his boss to take a seat.

"You don't have to hover, man. I'm good."

"Alright, then." Grissom clears his throat a little when he sits down, and reaches reflexively for a magazine. He's got a beer in his other hand and Nick leans back in his chair, wondering how long it will take for Gris to actually engage in conversation. At the lab, it can take ten minutes to get him to just look up from an experiment. Nick has always found that level of intensity incredibly hot. This time, however, Grissom manages to sit for almost fifteen minutes without really looking at Nick, and Nick uncomfortably sips his beer until he realizes it's empty.

Grissom startles when the doorbell rings. "What..." he looks up blinking as Nick stands up and heads for the door.

"Pizza. Hope you have money, 'cause my wallet was in my jeans." He smiles and notices that Grissom isn't really looking at him when he motions to the cash on the hall table. Nick pays, with a hefty tip, and already has a slice in his mouth by the time the pizza hits the dining table. There is a fresh beer waiting for him.

Twenty minutes later Grissom has transferred all their clothes to the dryer and they're back in the living room. Nick's on beer number four, and he thinks he should really slow down, because two slices of pizza isn't going to help absorb much of anything. He usually eats more. But then again, he usually doesn't have Grissom alternately staring at him and staring at his plate. Any easy banter they'd had in the garage over that damn chemistry set is long gone, and Nick wants nothing more than to shake Gris and ask him what the hell he did wrong. That, and to wipe away the damp line on Gris's neck where his still-wet hair is dripping down the back of his shirt.

Definitely no more beers, Nick decides.

Luckily, Grissom chooses that moment to pour them both a glass of scotch. Their fingers touch when he hands Nick the glass and Nick's sure he's imagining it when he sees Grissom's face flush. They take their respective seats and Nick sips at the warm liquid for a minute before Grissom says apologetically, "I'm sorry about your shirt."

"Nah," Nick replies easily, happy that Grissom's talking again. "It was an adventure, right? Though if that's what you do with a kids chemistry set, I'm amazed the lab is still standing."

Chuckling into his glass, Grissom finally seems relaxed, "Yeah, well, I wasn't joking about blowing up the garage as a kid." It's a long story, and a funny one, and at the end of it Nick's feet have found their way to Grissom's coffee table. The alcohol is making all the edges in the room seem soft. Grissom's leaning far back into the sofa now, another magazine lying forgotten in his lap. His shirt is rucked up a bit and Nick finds himself unable to stop staring at the line of pale skin over the waist of Gil's sweats. He's seen Grissom half naked not an hour before, but somehow that teasing line of skin is driving him insane. He knows he's staring, and he hopes he can pass it off later as an alcoholic stupor, but right now he doesn't much care.

The buzz of the dryer barely registers.

When Grissom doesn't move right away, Nick looks up at his face in question. His eyes are closed, but he's not sleeping—Nick can tell from the uneven breaths he's taking. It's not until he watches Grissom shift uncomfortably in his seat that it hits him. Oh, shit. That magazine is not there for decoration. Gris is clearly hard, and clearly trying not to let on, and clearly unable to get up and go deal with the laundry. Just the thought of it makes Nick bite his lip to keep from moaning. All the blood in his body heads instantly for his dick.

Now they are both hard, and both sitting there trying to pretend nothing is going on. It's almost funny, but not quite, and Nick is just drunk enough to not care about the difference between really good ideas and really stupid ones. Right now, he's got to do something and damn the consequences. The creak of the chair when he stands makes Grissom open his eyes, and Nick doesn't try to hide his erection, obvious through the loose pants. It's only two steps to the spot where Grissom is sitting, watching with wide eyes, and Nick watches them get wider as he drops slowly to his knees.

"Nick..." Grissom's voice is higher than usual, and a little out of breath. Nick reaches out and tosses the magazine aside.

Now or never, he thinks to himself, though he's probably gone too far to turn back now anyway.

"Gil," and Nick can't remember the last time he actually called Gris that, but he needs to do it more often, because he can actually see Gil's dick jump at the sound, "either you tell me to stop right now, or shut the hell up."

And he doesn't know when he got so bold-- the scotch is probably helping—but he's already hooking his fingers into the waist of Gil's sweats and tugging them down. He doesn't bother biting back the moan this time as Gil's hips lift reflexively, but he doubts it's even audible over the loud hiss Gil lets out when he's suddenly free, his dick hard and heavy against his stomach.

It's quiet enough to hear a pin drop. Gil doesn't say a word as Nick leans in to place open-mouth kisses along his hipbone, or when one of Nick's hands slides up and under his shirt. It's not until Nick's fingers wrap snugly around him that he makes any noise at all, and Nick almost comes at the sound of it, a low, stuttered groan as he throws his head back and bucks into Nick's touch.

Nick's suddenly incredibly sober. It's like his body is telling him remember this, because this is the last coherent thought you're gonna have tonight. When he leans in to taste Gil for the first time, he's rewarded with a soft sigh, and Gil's fingers thread into the hair at the nape of his neck, not pushing, just... perfect. It doesn't take long for Nick to figure out that Gil prefers good old-fashioned suction to any fancy tongue work, and even less time before Gil's fingers are tightening in his hair.

"Nicky, I'm... god," and Nick knows it's a warning, but he smiles against Gil's skin and he's ready when he comes, swallowing and stroking until Gil stills above him.

When he looks up, Nick has no idea what he's likely to see, so it's a flood of relief when Gil, hand still tangled in his hair, tugs him up with a rough "C'mere." He ends up sprawled over one side of the couch while Gil hovers over him, blue eyes incredibly bright as he leans in to kiss him. Nick expects it to be rough, but it's not; it's all gentle pressure and slow swipes of Gil's tongue against his and Nick feels a contented sigh building up in his chest. It gets stuck and twisted into a shuddered moan, though, when Gil's hand slips past his waistband and wraps around him. Their kiss broken, Gil abandons the 'no talking' rule in favor of murmuring low in Nick's ear, punctuating each phrase with a slick tug or a flick of his wrist. "Fuck, Nicky, do you have any idea how long I've wanted to do this? Wanted to taste you, taste myself on you? Do you have any idea how hard it was for me to not fuck you in the shower this afternoon? Just push you back against the tile and make you scream?"

Nick's hands are bunched in Gil's t-shirt and he's almost sobbing as Gil's words wash over him. Every nerve ending in his body is on fire, and when he comes, screaming Gil's name, it's blinding.

When he finally blinks his eyes open, Gil is looking down at him, bemused. "So."

"So," Nick manages, his voice hoarse.

"We really should talk about this."

Nick can't contain his eye roll. "Can it wait until I'm coherent?"

"If you can use the word 'coherent', you're coherent, Nick." He's still smiling, but Nick can feel the shoulder under his hand start to tense. He gives it a quick squeeze. "This was..."

"A hell of a lot of fun?" Nick supplies helpfully. Gil smirks.

"That too," he notes, and Nick slips a hand under Gil's shirt. "Nick..."

His tone is the same one he uses in the lab when he's about to tell Nick something he's not going to like. It's infuriating there, and it is here, and Nick is still just drunk enough to interrupt. "Look, if this is going to be about work, we'll deal with it. I've wanted to do this for a long time, and now that I have, I'm not gonna want to stop doing it, and all those workplace dating rules are facist anyway."

"It's not about work, Nick."

"Oh."

Gil sighs and moves to shift away. Nick tightens his grip on Gil's waist and pulls him back. Gil looks incredibly unhappy and Nick is certain he missed a page in the conversation.

"Gil, what? If its not about work, then what?" When he doesn't answer immediately, Nick adds, "You got a wife stashed in Tupelo? You took a vow of chastity? What?"

That gets a chuckle, but Nick doesn't loosen his grip.

"I'm really... God, Nicky." Gil stops pulling against him and instead collapses forward, his head resting in the crook of Nick's neck. "I'm not very good at this."

"At what?"

"This. Dating. Whatever. I-I don't do casual very well."

Nick snorts at this and Gil glances up. "Well, yeah. I kinda figured that. You're pretty intense, man."

"Yeah, well. Yeah." Gil sounds a little lost. "But there's more to it than that..."

"Look," Nick shifts so they're eye to eye. "You suck at people skills. I know that. You get completely wrapped up in work, and you're a little too into bugs, and your sense of humor is completely morbid, and you almost killed me in the garage today."

Gil's slightly miserable look morphs into confusion when Nick laughs. "Gil, I know all this stuff. I already know, okay? And, god help me, I still picture you naked at least once a day. You're weird. I got it. As for the casual thing... I'm pretty sure my feelings for you went past casual about a year ago, so I'm totally cool with skipping casual and going straight for serious. Now, was there something else, or can we get back to making out?"

The slow smile that spreads across Gil's face is priceless. "No, I think that pretty much covers it for now."

"Good." Nick leans in for a kiss, and wonders if he should mention that another shower wouldn't be a bad idea. When Gil's thigh slips snugly between his, he figures it can wait.