A/N and Disclaimer: I started writing this as a fill for Portal Kink, and then it eventually became a Christmas gift for my friend Deadly (deadlycrocker on Tumblr). I hope it turned out all right; I've gotten a few nice comments regarding it! Also, I don't own any of the characters or the setting; I'm just playing with VALVe's toys. Enjoy!

It had been about four months since GLaDOS had found Doug, dragged him to safety, nursed him to health, and thrown him onto the testing tracks. The promise of medication and his precious cube's safety had been enough to get him to work for her—and the resignation of a tired old man probably played a part in it as well. It was a comfortable arrangement in her mind; human tests were so much more satisfying than that of robots, thanks to the added risk of mortality. The only problem was the matter of hygiene. After weeks of demanding testing, Doug was starting to show signs of his humanness. Tracks of grease and sweat now marred her exquisitely clean facility. One thing was for certain: the rat needed a grooming.

"You're going to watch me shower?" He seemed to shrink into himself, and she could see him on the brink of rebellion. "I don't—I can't—"

"Please. I have no intention of watching you perform all of your disgusting human activities. I've checked the room to make sure you don't slip away, so I don't need to watch you, and I won't be able to once those doors close. Dispense your Aperture Science Handheld Portal Device in the receptacle outside the room. It will be returned to you after your hygienic restoration."

Of course, she was lying. Not about the return of the portal device—that would be a waste—but about his seclusion. After all, she could hardly be expected to trust him not to scrabble away through an unexamined crack in the wall, even though she had ensured multiple times that the washroom was inescapable. He'd always been far too good at discovering hiding places, and she needed to make sure she could see him at all times. It would be a shame to waste a good test subject—or, in this case, a desperate one. "Scrub hard. I don't even have an olfactory system, and I can smell you. I'll be attending more important matters. I'm sure you've left some paint lying around for me to literally watch dry."

He glared up at the large camera, looking more than a little suspicious, and relinquished the portal gun. The door closed smoothly behind him. Predictably, Doug searched the washroom for another recording device; it took a fair amount of restraint for her to keep herself from making a biting remark about his lack of trust. Nevertheless, he didn't seem to notice the tiny lens embedded over the shower head. That had taken some manoeuvering, but for all intents and purposes it was worth it.

Once Doug was apparently (and erroneously) satisfied with the privacy of the room, he began to undress, struggling a bit with the unwieldy long-fall boots. The test subject suit came off next, to be tossed into a mechanical laundry hamper. The machine automatically dispensed the clothing to be cleaned and replaced it with a fresh, overwhelmingly orange outfit. Socks were unceremoniously made subject to the same fate, and Doug began to shiver—from cold, GLaDOS imagined. Oh, hurry up, she thought to herself—though again, she stifled her own commentary. Similarly, she said nothing when he stripped off his undershirt.

Admittedly, Doug Rattmann was still a rather scrawny man. Years of near-starvation had severely affected his bone growth and the distinct lack of sunlight (outside of the hard light bridges) made his skin almost pearl-white under a dark layer of hair. Still, he now had regular access to food and he'd built some muscles from carrying around first his cube, then a portal gun so often. He was far from healthy, but he was . . . not horrifying to look at. For a human. A very dirty, scruffy, irritating human. She let the camera zoom in slightly.

He tossed a pair of old slacks away, and next his fingers slipped under the waist band of his boxers—she focused her lens. After all, he could make any sudden move now. Best to continue giving him close observation. He slid the underwear off, still shivering, and she found herself more than a little interested in the narrowness of his hips, in the dark, untended hair that had curled around his—

She gave a shudder—of revulsion, of course. Humans were just repulsive. And yet . . . she couldn't look away. It was like a train wreck, she reasoned (although a train wreck would be fun to watch); there was nothing else behind her insistence on continuing to direct her attention to Doug's very exposed genitalia. It was morbid curiosity and horror. Nothing else.

The boxers, too, were tossed into the hamper, to be replaced with Aperture Brand Heavy-Duty Non-Flammable Non-Tearable underwear—for later. For now, Doug stepped under the showerhead and turned on the faucet. He jumped back when it dripped a rusty brown liquid, but after a few seconds the water turned clear. He tested it carefully with his hand. Finally, he allowed himself to be enveloped in it, sighing heavily.

What was she doing? Surely she had better things to do than watch a pathetic human bathe. She shifted focus to observe ATLAS and Peabody's testing, but she saved a bit of attention for the washroom to monitor her capture. The two robots' brand of testing was less rewarding than Doug's, but it was still science. GLaDOS settled happily into her usual self, making caustic remarks whenever the robots did poorly (and whenever they did well). Her first statement made Doug jump and look around the room suspiciously—she hadn't turned off its speaker. She paid him no heed, and he slowly relaxed as much as someone like Doug ever would, perhaps reassuring himself that she really couldn't see him.

The little robots were entertaining in their own way, though their strangely human tendencies were more than a little irksome. They were created to work well together and they did so, completing tests so complex that they'd taken hours just to design. Still, it wouldn't do well to encourage the two with compliments; they had to be kept in their place. Besides, sarcasm was simply fun. GLaDOS found herself almost entirely immersed in testing when a small whimper caught her attention.

She scanned her cameras to find the source, zeroing in on the washroom again. Doug had managed to remove most of the grime from his body now, and his head was thrown back a bit, his teeth biting his lower lip. His hand, she realized, was wrapped around . . . around his primary sexual organ. A strange jolt went through her processors as he made another noise. Really, little rat? You are truly revolting.

It would be best to return to watching her tests, to ignore his deplorable urges and later delete the memory of it from her files. She didn't need to see this. Yet she let the camera zoom in again, taking note of the way he gripped himself, of how a finger would occasionally swipe past the tip of his member, of how he'd started to pant . . .

When he moaned for the first time, she'd completely lost track of the robot testing.

Doug pressed a hand against the wall, his other hand still working resiliently. GLaDOS felt peculiar, her sensors tense and almost warm. It was a familiar feeling, but she wasn't sure how; she was certain she'd never felt like this before. A flare went through her as he moaned again, louder this time, his hand pumping faster. She watched almost dizzily through the camera, suddenly very interested in those narrow hips and those strong arms, realizing for the first time how soft his lips looked, but always falling back to watch the fast, insistent stroking that sent more tremors through her mechanical body.

She moaned.

Doug froze, and so did she. The co-op bots looked up curiously. That did not happen. That did not happen. That did not happen. What was wrong with her? She was acting like a human in its weakest state, and worse, she'd let on that she could see Doug. The man in question was looking wildly around the room, his eyes wide. "GLaDOS?"

If she were a low enough person to swear—which she certainly was not—she would have done so. She searched desperately in her super-intelligent mind for some sort of solution, some sort of cover. Maybe if she acted like it hadn't happened, he'd think he imagined it. "Good job, Blue. A few more moments like that and you might be able to catch up to Orange. If by 'a few' you mean a number around six billion, of course."

The co-op bots stared at each other, Peabody chirping confusedly, but they were the least of GLaDOS's concerns. Doug's eyes narrowed suspiciously as he continued to scan the room. She thought she saw his gaze rest for a split second on the camera lens before darting away. Still frantic, she called out again. "Really, Orange, the way you talk about Blue is just cruel. Blue can't help being a little slower sometimes."

ATLAS and Peabody continued to look perplexed, but Doug's face seemed to relax a bit. Maybe her hastily-developed plan really had worked. He glanced down to the hand that still held his length, and she thought she saw a glint of mischief in his eye—no, no, she was giving him too much credit. He might be sneaky, she admitted, but he wasn't very clever. The hand began moving again at a tantalizingly slow pace.

Now would be the perfect time to ignore him and redirect her attention to the co-op bots, who had bemusedly returned to their test. Instead, she cut the speakers and watched Doug hungrily. It would be fine; he'd never suspect a thing. Besides, she was still feeling . . . odd . . . and she knew it had something to do with the Rat. It was only reasonable that she continue watching him to discern what was making her feel so unorthodox. It was just good science.

Doug's motions were slow, deliberate. It was as though he were drawing it out, teasing her—but that couldn't be the case, of course, because he didn't know she was there. Still, it was making her impatient. She wanted to force him to continue, to surround him with turrets until he moved faster, but she had a feeling that method wouldn't be particularly effective—especially as she was currently pretending she hadn't seen a thing. She settled for giving out a low whine, one that wasn't nearly dignified enough for a person of her stature. Inwardly, she felt a bit ashamed, but she couldn't stop herself. Faster. Go faster.

Gradually, he began to follow her unspoken directions. He started to groan, even harder now, and his free hand twisted in his hair to tug it roughly. As his hand picked up in speed, he swore, vulgar and human. The feeling of impropriety was stronger than ever, yet GLaDOS couldn't stop watching. She gave her entire attention to the moaning, squirming man, unable to contain her own cries. More, she thought, not without a level of disgust. God, more.

His hand was almost a blur now, pumping fast with the slickness of the water. Her circuitry felt as if it were buzzing, almost overworked with electricity, and the sounds he made in his ragged voice weren't helping anything. More! She could tell he was close, and she felt bizarrely close herself—though to what, she wasn't exactly sure. He became louder and louder as he worked, clutching to the wall, pumping harder and harder until he spasmed and cried out:

"F-fuck, GLaDOS!"

Her chassis nearly overloaded with shock as he climaxed, his cum quickly mixing with the falling water and swirling into the drain. He . . . he'd been . . . she couldn't even finish the thought, too stunned and appalled and . . . well, maybe a bit flattered. No! His opinion doesn't count—he's a human, and a weak one! He isn't even—you don't—

"Did you like that, GLaDOS?" Doug was panting and looking—to her horror—directly at the camera. "Don't be shy, now. I know you were watching me." He turned off the water and brushed his mop of hair out of his face, revealing a bitter grin. GLaDOS said nothing, panic rushing through her. What the hell was she supposed to say to that?

"You heard me. Which part did you like best? The sounds? The twitching? Your name? Or do you just get off on watching an old man shower?" GLaDOS was speechless. She hadn't known Doug to be the taunting type—but then, she'd never really seen him in a place of power before. Embarrassment burned hot within her at being caught in such a contemptible position, but she pushed the feeling away. This was ridiculous; she was the one in control here. She wasn't going to let herself get taken down by the likes of Doug Rattmann. Irritated, she turned the speakers back on.

"When was the last time I gave you medication? I must have missed a dose; you're clearly delusional." Her voice was cool and unshaken. There were benefits to not having vocal folds that trembled under pressure. Doug's grin, however, didn't drop.

"So you can hear me. Got a microphone connected to that little camera of yours?" He reached up to poke at the lens, effectively masking it with a water droplet from his finger.

"Don't touch that," she snapped—then realized her mistake. "I . . . I mean . . ."

Doug laughed, his rough voice resonating in the small space. She couldn't see him clearly anymore, not with the water still obscuring her view, but she could imagine the smirk on his face. How could she have been so stupid?

She was also facing a problem she hadn't anticipated. All of that . . . excitement . . . had built something up inside her, something that she didn't know how to release. It was like . . . she hesitated as the word itch came to mind, but it did give her a spark of realisation: she felt exactly the kind of tension she usually suffered while waiting for someone to finish a test. The very thought frustrated her; there had to be a way to fix it, to free her in a wave of euphoria. Perhaps if Doug touched her the way he'd touched himself . . . again without thinking, she let out a computerized sigh.

The blurry shape that was Doug stilled, and he stopped laughing. When he spoke again, his tone was a mix of curious and suspicious. "What were you just thinking about?"

The scientists had equipped her with more sensors than was technically necessary; they had originally been used to simulate pain in an attempt to keep her from lashing out. Her chassis and cables were especially sensitive, and with the right touch, she imagined her sensors could finally be put to good use. Her voice was calm as she provided an elevator outside the washroom—one that would lead directly to her chambers. "Please proceed to the next test. Clothing will not be necessary." Before Doug could protest, the laundry hamper swallowed the clothes it had provided, offering nothing as a replacement.

He seemed to hesitate, though she couldn't be sure with such impaired vision. She was about to send the Party Associate after him when he stepped out of the shower onto the Aperture Science Military-Grade Body Dryer, which blew air at him from all directions until he was reasonably dry. "Fine," he said softly.

"Fine?" Her voice was as calm as ever, betraying no sense of anticipation or nervousness.

"Fine." He laughed quietly as he stepped into the lift. "It'll be my pleasure."