He rushed into the shower, wincing as the scalding water hit his back before he had a chance to adjust the temperature.

Still, the stabbing pain from those droplets against his skin wasn't sufficiently agonizing to compete with the horrifying, visceral sense of shame and humiliation he felt knowing that Emily had been watching him jerk off into the sink while he held her panties to his nostrils.

"Reid?"

Her voice was surprisingly gentle, even kind. He was not about to let that voice trick him into forgiving her, not after the reservations he'd had from the very beginning about allowing her into his apartment, into his most private space. She had violated that space from the moment she'd first touched him at the compound and on the plane, and it was going to end. It was going to end right now.

"Spencer, I know I shouldn't have watched you like that. I thought you were in the shower, but when I opened the door to grab my hairbrush, I saw you there and I just ... wanted to see more." Emily paused, and when there was no response from behind the shower curtain, she added, "There's nothing to be embarrassed about, you know. I mean, we all do it. It's human."

Her casual "we all do it" resulted in an unwanted stirring in his groin, which only strengthened his resolve to get her out of there - and the sooner, the better.

"There's a card for a taxi service on my desk," he replied tonelessly. "They can take you home from here."

Even over the loud drumming of the shower, he could hear her exasperated sigh. "Did you ever notice how sometimes this job takes over our entire lives and turns us into these unemotional, one-dimensional versions of ourselves? How, because of this job, we're essentially conditioned to suppress all of our fears and desires, and how that spills over into our personal lives, too?"

"Maybe for you," he snapped angrily. "But when I'm at work, I'm just me. I don't need to suppress anything."

This, of course, was a bold-faced lie. He understood the concept of suppression better than perhaps anyone else on the team, since he was the only one who was forced on a daily basis to suppress his emotions - his fears and desires, as she'd worded it - for the woman he'd been hopelessly in love with since the moment he watched her walk through the door at the BAU, for the infatuation that had only grown stronger over time.

"If I leave now, we are never going to be able to work together again," Emily told him quietly. "You do know that, don't you?"

An unexpected panic ran through him in rivers. He hadn't thought about that. About how, if he couldn't look at her now, he'd never be able to look at her again. About how, if they didn't talk about what happened, they'd never be able to talk to one another again. No, he couldn't have that. He couldn't lose her like that. He'd always known he could never have her in the way he desperately wanted to have her, but now he realized with sudden clarity that he could also never handle losing what they did have. Because as small and insignificant as it might be to her, it was everything to him.

Reluctantly, he turned the shower off and asked her to wait in the bedroom while he got dressed. He toweled himself off, self-hatred flooding his synapses when the lightest touch of the soft material against his genitals prompted yet another erection, one that didn't diminish even against the tight briefs he'd hoped would contain it. Gritting his teeth, he pulled on an oversized CalTech T-shirt and a pair of loose-fitting sweatpants, closing his eyes and focusing on his breathing until he felt himself softening, comforted by the knowledge that, if he did become physically aroused again, the evidence would remain hidden under his clothing. Hidden from Emily.

Nothing could have prepared him for the sight he witnessed when he walked out of the bathroom: Emily, with her jeans and panties crumpled on the floor next to his bed and her grey college T-shirt pushed up to reveal everything from her smooth stomach down to her gazelle legs ... and then there was her finger. Her finger rubbing small, slow circles against her clit.

He found himself incapable of speech, his jaw dropping and eyes widening in shock and confusion. The way she was touching herself so casually, the way her straight white teeth were biting down on her pouty lower lip, the way her dark brown eyes didn't waver from his gaze for a moment, stunned him.

"I thought that maybe if you watched me," she finally explained in a husky voice, "you'd be less embarrassed about me watching you. That we'd be even."

At that moment, transfixed by the sight of her openly masturbating on his bed, he didn't care about being watched and he certainly didn't care about being even.

All he cared about was seeing more.

He was rock-hard as he watched her, his balls as heavy as an overpacked grocery bag, pre-come dripping from his dick like a leaky faucet.

After about five minutes of watching her finger drawing tight, pressured circles around her clit, she groaned, "This isn't going to work."

The wounded dismay that stung him to his core must have shown on his face, because she quickly continued, "I'm a very ... visual person. I usually close my eyes and fantasize about something. But I don't want to close my eyes. So I need you to be my visual stimulation."

His heartbeat accelerated and insecurity struck him like a lightning bolt. What, exactly, did she want him to do?

"I want you to touch yourself while you watch me. I want to watch you touching yourself while you watch me." Her tone was so matter-of-fact, so breezily indifferent, that it took him off-guard. Then again, he was practically bursting through the confines of his clothing already ...

Self-consciously, he pulled down his sweatpants and his briefs and allowed his cock to spring free, sighing in relief. When he tentatively glanced up at her, the mere effect of seeing his body had clearly affected her: she let out a small whimper and began to increase the pace of her finger against herself.

Not wanting to come too soon - terrified of coming too soon - he kept his eyes fixed on her as he slowly ran his right hand from the base of his cock to the tip and back down again, briefly cupping his balls when the sensation proved to be too much.

It seemed to him that they took their cues from one another: he would increase the speed of his hand against himself and then she would increase the rhythmic pressure against herself. He would pause to stroke himself more slowly, and she would switch to a less frantic, feather-like touch.

He tried to make it last - to make himself last - as long as possible, but after only a few minutes had elapsed, he knew his orgasm was imminent and he ceased to care about waiting for her. He jerked faster, his closed fist flying against his cock, his breathing ragged and unsteady, as he felt it beginning to build within him.

And that was when Emily moaned loudly, her body arching off of the comforter and her legs trembling. It wasn't until the glorious first throb of warmth escaped him that he realized she hadn't yet reached orgasm; as he shuddered and squirted onto the edge of the bed below him, he saw her eyes close and her whole body quake erratically while clear liquid glistened at her opening. He struggled to keep his eyes open, watching in fascination as she came. And came. And came again.

By the time she was finished, he'd already pulled his underwear and sweatpants back on, the sticky residue from failing to wipe himself off cooling and hardening in his briefs.

She was staring at the ceiling, trying to catch her breath, when he lowered himself onto the bed beside her, unsure of what to do next. Should he kiss her? Cuddle with her? Talk to her?

All of those options seemed desirable.

Emily, however, shifted into a sitting position and reached for her panties and jeans. "I really needed that after a day like today," she told him, glancing at him for a moment. "Much more relaxing than a cup of coffee."

He flinched. Was that all it was to her? A way to unwind? An alternative to coffee?

"Don't you want to - I mean, don't women like to ... afterward, I mean -" he stuttered.

The look she gave him made him feel like a pathetic teenager. "Oh, Spencer, you're so cute."

Cute? He was so cute? His face blushed crimson at the back-handed compliment.

"Look, all we did was something we would have already been doing on our own. We just did it together. No big deal, right?" Emily shrugged indifferently and stood up to zip and button her jeans.

No big deal, right? Right?

Wrong.

It was a big deal. It was a big deal to him. How did she, a seasoned profiler with the FBI, fail to see that? How did she, a human being, fail to understand that?

But before he could find the courage to ask, she was already on her BlackBerry, arranging a car service to drive her home.

"See you tomorrow," she called over her shoulder after collecting her go bag from the bathroom and walking out the front door with a grateful smile.

And, more than anything else he'd seen that day, the image of her leaving so abruptly was the one that remained with him as he shut off the lights and tried to fall asleep.

Because it wasn't watching Emily come that had affected him so profoundly.

It was watching her go.