JJ stood in the doorway to her office and found herself scowling as she looked out across the bullpen. That morning, she'd seen Emily and Morgan arriving together, laughing as they walked to their desks. From that point onwards, she'd been in a foul mood. Poor Spencer had been on the receiving end of her short temper when he had, with hindsight, completely reasonably, suggested that a case that he'd been allocated might be better suited to Morgan. Her sharp reaction had sent the young doctor scurrying away with a confused look on his face.

And now, she'd happened to open the door to her office, intending on refilling her coffee mug, just in time to see Morgan leaning over Emily's desk. Whatever he'd said to her had made her laugh and swat his arm, and the eye contact between the two of them made JJ's stomach churn.

Turning around, she closed her office door again and made her way back to her desk. She could feel heat rising in her cheeks and was suddenly unsteady on her feet.

Until that moment, she'd been quite content in her bubble of denial. But she could no longer ignore the physical signs that her body was giving her.

She was jealous.

There had been an initial spark of attraction the very first time that Emily Prentiss had walked into her office. At that point, it had been purely physical. But as she'd got to know Emily, the attraction had grown. Until recently, she'd told herself that it was nothing more than an unrequited crush on a colleague, or rather, a friend. And she'd never let her feelings come between either their friendship or their working relationship. But part of that was realistically because she found comfort in the fact that Emily's working life was as busy as hers, leaving very little time for cultivating any romantic relationships outside of work. She was totally fine with the fact that she couldn't have Emily when, as far as she knew, nobody else was getting her either.

But now she knew about Morgan. And it meant that she was second guessing every interaction that they had. She saw a sexual undertone in every exchange of words, every glance between her two colleagues. And it didn't matter that Emily had been very clear that there was no suggestion of anything more than sex between the two of them. JJ still found herself imagining that the two of them were secretly in a relationship outside of work. When she'd left Emily's apartment that Friday night, she imagined that the two of them had spent the whole weekend together, acting like a couple. And the thought made her feel sick.

It wasn't like she didn't see the attraction with Morgan. In fact, she had even enjoyed having sex with him. But it didn't compare to how she felt about Emily.

Having finally been honest with herself, she gave herself a talking to, resolving that whatever was going on outside of work, she couldn't let it interfere with her job. She picked up her mug again, and headed out to refill her coffee.

As she stepped out of her office, she caught sight of Emily walking away from her desk and heading towards the bathroom. She paused for a moment, second guessing her immediate instinct to follow her. Deciding to just go with it, she crossed the bullpen and entered the bathroom about thirty seconds after Emily.

Once inside, she checked that only one stall was occupied before putting down her mug and simply waiting. Her heart was pounding and she had to wipe her palms on her thighs to rid them of sweat.

It seemed like Emily took hours to emerge, when in reality it was probably only a minute or two. As she stepped out of the stall, she first caught sight of the blonde in the mirror, and turned to smile at her as she washed her hands.

"Hey Jayje" she smiled.

"Hey"

"You ok? You've been shut away in your office more than usual today. Local PDs giving you grief?" Emily asked as she turned to dry her hands on a towel.

"Yeah uh…something like that"

As the brunette turned back to face JJ, she could see the change in her eyes. She stood still and simply waited for the blonde to step towards her.

JJ was unable to hold back. She slid her hands into the brunette's hair and pressed her mouth to Emily's, inhaling deeply. Hearing the brunette whimper, she parted her lips and began to kiss her forcefully. Her tongue took control of Emily's mouth, and the brunette backed herself up against the wall, her hands gripping JJ's hips firmly to pull her body against her.

The blonde pressed her pelvis against Emily, and was rewarded by the feeling of the brunette's hands sliding around to grope her ass. Her own hands began roaming desperately as the kiss grew breathier, sliding between their bodies to cup Emily's breasts before returning to her hair.

Finally, the kisses slowed, and JJ took a step back, breaking the contact between them. As she caught her breath, she watched Emily stay pressed against the wall, slowly opening her eyes to look at the blonde.

Leaving the brunette with a knowing look, JJ turned and picked up her mug, and walked out of the bathroom without as much as a glance behind her. Her legs were shaking, but she hoped that nobody noticed as she headed straight for the coffee machine to fulfil her original purpose in leaving her office.

Once she'd returned to the safety of her desk, she forced herself to turn her mind back to her work. Flicking through files, she had to keep chastising herself for letting her thoughts drift to Emily.

She felt a vibration coming from her bag that was on the floor by her feet. Pulling out her personal cell phone, she saw that she had a new message from Emily.

Emily: You can't just kiss me like that and then walk away

Her body was immediately overcome by a tingling feeling. There were a number of different ways that she could play this, but she decided just to go all out.

JJ: Would it have been better if I'd fucked you right there in the bathroom?

Having sent the reply, she placed her phone in her back pocket. She knew that she had to see for herself how it affected Emily. She picked up a file that she had a completely non-urgent query for Reid on, and made her way to his desk, which was conveniently located directly across from Emily's.

As she'd hoped, one brief question to Reid lead to him giving a drawn out response which she only half needed to listen to. Her eyes kept subtly darting across to Emily, and when the brunette nonchalantly reached into her jacket pocket, JJ couldn't tear her eyes away from her.

The blonde could tell the exact moment when Emily read her message, as the brunette's cheeks flushed and she visibly swallowed. She typed a reply, and JJ felt a vibration in her pocket. Having allowed Reid to finish his long-winded answer, she picked up the file and pulled out her phone as she walked away from his desk.

Emily cleared her throat before calling out after her "JJ?"

The blonde turned back to face her "Yeah?"

"I have a few things on this case that I could do with your input on. Have you got a spare minute if I bring the file up to your office?"

"Sure" JJ smiled at her "Bring it up whenever you're ready"

As she walked away, she read the reply that Emily had sent.

Emily: Yes. You make me want to break all the rules

Hurrying back to her office, she left the door open and simply perched on the edge of the desk. She had no idea what to expect when Emily entered her office, or even how long she'd have to wait. But she knew that she wouldn't be able to concentrate on anything else until she found out.

Luckily for her, she barely had to wait for a minute before Emily appeared in the doorway, file in hand.

"Is uh…is now good?" the brunette asked, perhaps a little louder than was really necessary.

"Come on in" JJ replied with a smile.

Emily closed the door behind her and slowly crossed the room without speaking. She dropped the file on the desk, and came to stand directly in front of the blonde, encouraging her to part her thighs so that she could stand between them.

"You…" she said softly, running a hand lightly up JJ's side "are really, really bad"

"Oh yeah?" the blonde breathed, hooking her fingers over Emily's off-centre belt buckle.

"Yeah" Emily confirmed, leaning in so that she was close enough to kiss the blonde, but leaving the slightest of gaps between their mouths.

"I'm not the rule-breaker here" the blonde teased, tilting her head to the side slightly.

"Really?" Emily raised her eyebrows "I'd say you broke the 'not in the office' rule first"

"And uh…did I ever agree to that rule?"

"Jennifer…"

The desperation in Emily's voice was intoxicating, and the blonde brushed their cheeks together, tilting her head down so that her breath tickled the brunette's ear.

"I think…" JJ breathed "that I'd rather make my own rules"

"And what does the Jennifer Jareau rulebook say?"

"It says I can turn you on anytime I want…so long as it's safe"

"Safe, huh?" Emily pulled her head back slightly so that she could make eye contact with the blonde.

"I would never do anything out in the field" JJ replied honestly "I would never distract you or put anyone at risk"

"I think you underestimate how distracting you can be"

The blonde blushed, tracing the shape of Emily's belt buckle with her fingertip.

"And here, in the office?" the brunette continued "Is this safe?"

Emily slid her hands down the blonde's thighs, hooking under them to hoist JJ up onto the desk. She pressed her pelvis into the blonde, leaning forwards slightly as JJ instinctively grabbed onto her shoulders.

The blonde slowly shook her head, swallowing "This feels like a different kind of dangerous"

"Do you have any idea…" Emily whispered, trying to keep her breathing under control "I said I had fantasies…do you have any idea how many times I've thought about fucking you right here on this desk?"

"Fuck" JJ gasped.

"So next time you come to work wearing one of those skirts of yours…I want you to know that I'll be imagining having you in exactly this position, only I'll have bunched your skirt up around your waist. I'll take off your underwear, and you can bet I'll be keeping it to remind me of how I've fucked you in your office"

"That's…oh god…" the blonde panted "that's what you think about?"

"Every. Single. Time" Emily replied firmly.

"That would definitely break the 'not in the office' rule"

"Oh I know" the brunette agreed "and that's exactly what I meant when I said you make me want to break all the rules. You know how I'm usually in control of everything I do?"

"Just a little bit, yes" JJ smiled.

"Well you make me lose that control. When I looked at you, I always wondered what it would be like to fuck you. Imagined what it would be like to touch you. But I kept that inside, kept my self control. Only now, I know exactly what that feels like. I don't need to imagine it. And so when you kiss me like that…when you put your hands on me…all the rules seem to disappear"

Keeping one hand wrapped around the blonde's back, Emily reached up with the other and slid it around the back of JJ's neck. Their eyes locked together and she leant forwards, leaving a lingering kiss on her lips.

Slowly Emily backed away, looking at the blonde still sat on her desk "I should go, before I do something that gets us both in trouble"

"Yeah" JJ stood up, straightening out her clothes before picking up the file that Emily had left on the desk and handing it to her "here, don't forget this"

"Thanks" the brunette smiled, taking the file "I'll catch you later, yeah?"

"Absolutely"

As Emily opened the office door, she turned back to address the blonde.

"Thanks for your help Jayje, invaluable as always"

JJ laughed and shook her head as the brunette walked away. Things had just got interesting.