Title: Never Assume
By: reversedsam
Pairing: Cath/Sara
Fandom: CSI: Vegas
Rating: NC-17
Disclaimers: They're not mine, but I promise I'll have them back by midnight.
A/N: All mistakes and British spellings are mine.
Summary: Grissom shouldn't make assumptions.

***

Catherine and I are at home curled up in bed. My body is still tingling from her touches. She's snuggled into my side; head resting on my shoulder as I run my fingers in random patterns across her back, I know this relaxes her.

We argued earlier, something we do often, always have. This time however her words from the locker room earlier have been playing on my mind, and as much as I hate to break the mood I need to talk to her.

"Catherine."

"Mmm."

"Do you really worry that I'll leave you for Grissom?"

She immediately lifts her head to meet my eyes.

"Honesty? Yes, sometimes."

I try to say something but she cuts me off.

"Shh baby, let me finish. Yes I worry sometimes, especially, the past few weeks, the way he's been acting with you, but after today." She smiles. "I know how private you are, what you did today can't have been easy for you. It wasn't something you had to do, but you did it anyway, just to show me how much you love me. So, I don't think it'll be something I'll worry about in future."

"Good because I never want you to doubt how much I love you." I say, honestly.

"I never doubted that Sara, just sometimes, stupid insecurities get the better of me."

"Well, whenever they do in future, talk to me. I love you and I intend to be here as long as you'll have me."

She doesn't reply, just kisses me and places her head on my shoulder, tightening her hold on me.

Six hours earlier...

Why the hell do I do this job again? I think to myself as I sit outside some seedy motel filling up buckets with ice in one hundred degree weather.

Oh yeah, to help catch sick bastards like the ones we are trying to catch now, the ones leaving a trail of dead bodies behind them. I get my reminder as Grissom pulls a knife from the huge cooler we're processing.

He gives it to Warrick and asks me to processes the blood as he takes Nick to check the room. I wish Nick would just talk to Grissom and get it over with, this atmosphere is not good.

I see Catherine's car pull up and can't contain my smile. Although we're on the same case, she's been with Grissom and I've been with Warrick so I haven't seen her since she left my apartment this afternoon to go get Lindsey. Ordering me to get some rest before going to work.

I feel the butterflies that I get whenever I see my girlfriend start to flutter in my stomach.

Keeping my eyes on her car I watch the door open and see her step out. My breath catches as I finally get a look at her. Oh. My. God.

She cannot wear that to work. Work, where I have to concentrate. Concentrate on something other than her. I think I stop breathing as she grabs her kit and starts walking towards us.

My eyes have a mind of their own as they move up her legs, god those pants must be painted on. I can't stop myself as I take in her slim waist, flat stomach, perfect breasts and finally her gorgeous face.

She's smiling when she reaches us and I sit, looking at her as she asks Warrick were Grissom is, thanks him for his answer then turns her gaze to me when he turns back to the cooler.

My eyes are still wondering across her body until I catch sight of her grin. She winks at me when I make eye contact. She's fully aware of how she affects me, how my body burns up at just the sight of her. I don't speak, I'm not sure I could, besides, I'm sure my eyes are conveying exactly what I'm thinking.

I force myself not to turn and look at her again when she leaves to go help with the room. How the hell am I meant to work now?

An hour later Warrick heads off to the lab to get the blood we've found processed, leaving me to check the cooler once more. He's barely out of earshot when I feel a hand come to rest on my back.

"Hey baby." I hear over my shoulder. I wonder for a second if turning around is such a good idea, it won't help me keep the concentration I've only recently managed to regain.

"Hey." I reply as I turn around anyway, who needs concentration.

"You finished here?"

"Just about." I say absently. God she looks so sexy today.

"You seem distracted." She teases.

"Hmm, you seem to be the cause of that distraction." I tell her.

"Me?" She says, pretending to look shocked. "I've been minding my own business, processing the scene. How could I possibly have distracted you?"

"You know, I'm not sure. Could be something to do with the skintight pants and that little top."

She looks down at herself and smiles before replying. "You know, I thought you might appreciate these."

"Oh I do." I reply, my voice dropping a little. "I'll also appreciate them on my bedroom floor later, just after I've thoroughly...appreciated you." I smile.

"Sara." She gasps. Her eyes close momentarily, no doubt because she's having the same thoughts as me right now.

Our conversation is interrupted by Grissom's arrival. I'm slightly thankful though, I have zero control when it comes to Catherine.

"Room is cleared. Catherine, get those coins to the lab ASAP please."

"On my way now." She replies.

"Good, thank you. I'm grabbing a break, I need something to eat."

"Okay, keep your cell on; we'll call if there's any developments." I tell him as I finish labelling the last bucket of ice.

"Actually Sara I was hoping you might join me." He says with a smile.

I watch Catherine shoot him a look. The guys don't know about us yet. We've only been together a few months and decided to keep it to ourselves for now. Although I get the feeling that will be changing soon.

"I'd like to spend some time with you." He tells me.

Grissom has been acting strangely for a few weeks, showing an interest in me, flirting even and Catherine is getting increasingly pissed of with it. Rightfully so. I know if roles were reversed. I'd feel just as she does. She's already both upset and pissed off about the Sam Braun case, so this is the last thing she needs.

I make a note to talk to her about telling him. I want him to know I'm taken.

"Thanks Grissom but I really want to get this done." I tell him.

"Okay. Some other time?" He asks.

I just nod and smile, hoping he leaves it there.

"Good. See you later. Catherine let's get going. I want those coins done."

She nods and heads off to her car without a word. Yeah, definitely talking to her later.

A few hours later I'm back at the lab. We've just had a meeting about the case. As the meeting finished and everyone was leaving Grissom decided to see if I wanted that 'some other time' to be after shift.

I watch anger flash through Catherine's eyes as she practically storms out of the room. Screw Grissom. I need to talk to her about this now.

I tell him the conversation will have to wait and leave him looking confused as I hurry after Catherine. I catch sight of her in the locker room and follow her, closing the door behind me, giving us a little privacy.

"Catherine, you okay?" I ask as I walk over to her.

"No. I'm fucking furious. I have to stand around and watch him flirt with you. Hear him ask you out. Watch the way he looks at my girlfriend when he thinks nobody is looking. Watch his little touches to your arm or see his hand on your back. I swear if he does it once more, I'll kill him."

"Please don't be angry with me Catherine, I can't..."

"I'm not angry with you Sara." She cuts me off. "Not at all. I'm angry with him and he doesn't even know about us so he isn't to blame either, but I can't help it, I still want to hit him."

Sadness flashes across her face as she raises her eyes to mine. "You know I get insecure too Sara, You think I don't worry sometimes that you'll leave me for him?"

How can she think that? I'd never leave her, I love her. I move to stand in front of her and cup her face in my hands. "Catherine, I love you, so much, don't ever think that I'd leave you for him, or anyone else for that matter. It's you I want." I tell her, hoping she realises the truth of my words.

I lean in and kiss her as I finish speaking and am more than happy to see her smiling as I pull back.

"Thank you." She whispers. "I needed to hear that."

"I hope you believe it because you're stuck with me now Willows."

I'm glad to see her smile. I know she wasn't angry, insecurities get the better of us all at one point, I'm just glad I was here when she needed me.

"Yeah, well it's a good thing I like having you around isn't it Sidle?" She teases back.

"We should tell him, I want everyone to know about us."

She's about to reply when Grissom shouts from outside the locker room, cutting me off.

"Sara? Catherine? Is everything okay?"

I curse his timing as I watch Catherine's head snap towards the door.

He obviously knows we're in here and he'll open the door if we don't answer.

I keep my eyes on her and I'm a little stunned when the anger I was expecting doesn't appear, instead a seriously mischievous look crosses her face.

Oh god, what the hell is she up to?

Her hands move to my hips and she gently pushes me back until I'm trapped between the lockers and her body. I move my hands to her waist in an attempt to stop her movements.

"Catherine? What are you...?"

"You said we should tell him." She smirks.

I try to reply but my words are cut off by her mouth as she leans in and kisses me. Despite myself I automatically respond to her kiss. Happily granting her tongue entrance to my mouth when she requests it. I know I should be stopping this but with the way she's kissing me right now, I don't seem to care who walks in.

Her mouth moves to my neck, despite my groan of disappointment when she breaks our kiss.

I lean my head to the side, giving her better access as she slowly kisses her way down my neck, then back up to my ear.

Her hands slide under my top and I arch into her touch. I vaguely register Grissom calling us once more; I should probably try to stop this.

Her nails rake across my stomach and I bite my lip to stop myself moaning.

"Ah ah, don't hold back. I want to hear you moan for me baby." She husks into my ear.

"Not alone." I manage to hiss out. Okay so we've almost been caught in compromising positions before but never intentionally set out to put ourselves in one.

"I know. Let him hear. Let him hear those sexy little sounds you make when I'm touching you, when I'm taking you. Then he'll know you're mine."

As she speaks she slides one hand up to cup my breast, slowly massaging, and the other hand moves down to the inside of my thigh. She rakes her nails up my thigh, something she knows is a serious turn on for me, even through the material of my pants it sends shivers down my spine. I somehow manage to hold back another moan.

Grissom shouts once more and somewhere in the back of my mind I register the fact that he'll come in soon if we don't answer. I make a conscious effort to calm my raging hormones. An effort that is wasted when Catherine decides to turn the heat up.

She runs the tip of her tongue along my ear as her nails rake up the inside of my thigh once more, then her fingers focus on my nipple and before I can even think...

"Oh god Catherine..." Leaves my mouth in a guttural moan. He had to have heard that.

It takes me a second to realise that she's stopped touching me, that I'm no longer pinned to the locker. I open my eyes and see she's stepped back from me and is giving me a seriously amused grin. Oh she thinks this is funny. She knows Grissom will have heard.

Grissom shouts once more, his voice tentative this time and I hear the locker door slowly open. I quickly decide turning the tables would be only fair. After all, we did decide to tell him. And I want to prove how much she means to me.

I give her a mischievous look of my own as a grab her hips and turn her around, quickly leaning in to capture her lips. She tenses for only a second and I can't help sighing as I feel her relax against me, bringing her hand to my cheek and deepening the kiss.

I hear a cough from behind us, obviously Grissom is trying to get our attention but I couldn't care less right now, kissing her is far more important. He coughs once more and Catherine slowly pulls back, resting her forehead against mine.

"Thank you, I love you." Her voice cracks as she speaks.

"I love you too, never doubt that."

Her hand drops from my face and she laces her fingers through mine, squeezing my hand gently.

I hear a yet another cough over my shoulder so I step back from Catherine and we turn to face Grissom.

He looks shocked. Not something that's easy achievable in our line of work.

"Can we take the rest of shift off?" Catherine asks as if nothing is out of the ordinary.

Grissom nods mutely, shock still clear on his face.

"Thanks." Catherine says as she walks towards the door, taking me with her.

"I'm sorry." I hear just as we're about to leave the locker room.

We both stop and turn to face Grissom. The shock has been replaced by sadness, and I can't help feeling bad for putting it there.

"Had I known you were together I never would have..." He trails off, no doubt unsure how to word it. I'm grateful to him for saying that, for letting her know that whatever he'd assumed would happen between us, he now knows it won't, it never would have.

"You know now. It doesn't happen again, okay?" Catherine tells him. All traces of the anger she felt before fading as she speaks.

He nods before speaking again. "Congratulations." He says, then turns and walks out of the room, managing a small smile as he walks away towards his office.

"Should we go after him?" I ask.

"No. Let him take it in. We'll talk to him tomorrow. We'll tell the rest of the team tomorrow as well." She replies as she heads towards the exit, never letting go of my hand.

"You know he'll take us off the case for blowing work off don't you?"

"Let him. Unfortunately, we always have more cases."

"Let me take you out." I say as we reach the car.

She turns to look at me, giving me a smile before replying. "I'd like that. Take me home so I can change."

We climb into the car and I lean over to give her a quick kiss.

"You're joking right? Did you not catch how sexy I think you look in those?"

"Thank you, but..."

"Nope." I cut her off. "I want to take you on a date, which will not happen if I take you home to change first."

"Why?" She says, raising her eyebrow.

"Because." I say as I steal another kiss. Lowering my voice and letting my eyes wonder over her body as I speak. "I promised myself as soon as I saw you today that when those clothes came off you, it would be me removing them, slowly. Kissing every inch of you I reveal as I do so, and I fully intend that to happen as soon as I get you home."

I hear her quick intake of breath and smile to myself. Proud of being able to affect her this way.

"For future reference, the threat of you making love to me will never be a deterrent baby." She smiles. "So you're gonna have to do better."

I smile at her before continuing. "Now I need a reason to want to spoil the love of my life?" I ask. Giving her my best innocent look. "To take my gorgeous girlfriend out and show her off?"

"Well when you put it that way." She shrugs. "Who am I to refuse?"

***