The first time Penny used her power, she didn't even know that she'd done anything.

After a four-month dry spell, the blonde beauty was ready for some action. To this end, she'd followed her friends to a classy nightclub, hoping to meet a hot guy to hook up with. She wasn't normally one for one-night stands, but she was still recovering from her last break-up, and a boyfriend was just not on her priority list. She scanned the dance floor first, but quickly turned her attention to the bar as she realized that all the attractive men were already with someone. I'll let them come to me, she decided, stepping up to the bar and ordering a wine cooler.

When a very cute guy sat down next to her, Penny reconsidered her plan, deciding that it wouldn't be so bad if she initiated things, after all. Big ol' five, said a voice in the back of her head, and for some reason, she found it easy to imagine Sheldon's voice. But then she shook off the notion and turned to the man next to her. "Hey there, cute stuff," she purred, licking her lips. The man looked over, dark eyes widening in surprise.

"H-hi," he stammered, and Penny was both surprised and pleased to find that he was flustered already.

This ought to be easy, she thought with a smirk. "I'm Penny," she said aloud, extending her hand.

The man beside her twitched and frowned. "Drew," he responded after a moment, shaking her hand. Penny's spirits sank as her eyes fell upon the loop of metal on his ring finger.

"You're married," she stated, unable to keep the disappointment from her voice. She might be up for no-strings-attached sex, but not with a married guy.

Drew's brow wrinkled, and a pained expression crossed his face. "Yeah," he responded slowly. "Th-that's right." He shook his head, as though trying to clear his thoughts. "I'm sorry," he said hesitantly. "I love my wife..."

"Oh, of course!" Penny answered quickly. "I wouldn't want to mess with that..." she trailed off as she took notice of Drew's suddenly shallow breathing. "Are you okay?"

His eyes shot wide open. "I—just fine!" he answered, far too quickly to believed. "I'm sorry, I..." he swallowed hard. "I really have to get out of here." Slapping down money on the bar for the drink he'd barely touched, the handsome man hurried away. As Penny stared after him, her confusion overwhelmed any desire she might have had for sex. What the hell just happened? she wondered. She mulled over her drink awhile longer as she thought about the perplexing encounter, but as she finished up, the event was no clearer than it had been when it happened. With a sigh, she decided to put it out of her mind and go home. Sex could wait until another day.

Unfortunately, as Penny slowly discovered, it was not something that could be put out of her mind. The next night, she ventured out once more in search of fornication. But, much to her shock, the same thing happened. It wasn't the same guy, of course, but there was no mistaking the response. Both men she approached responded by freaking out and running off. It's enough to really depress a girl, she reflected that night at home as she chugged tequila. Obviously, something was going on with her, but what? Guys had never acted this way around her before, and she'd be damned if she was going to let it keep happening. Because if she couldn't even talk to a guy, how the hell was she supposed to have sex? That was an idea she wasn't willing to entertain.

Mind made up, Penny set down the tequila bottle and marched out of her apartment, rapping loudly on the door across the hall. If anyone could help her figure this thing out, it was Leonard and Sheldon, right? After all, not only were they guys (well, sort of, filled in a voice in the back of her head), but they were geniuses. Surely they'd be able to come up with an explanation.

The door swung open to reveal Sheldon, an eyebrow raised as he looked down at Penny. "It's 9:15," he stated, lips curled back in annoyance. "I am about to go to bed."

"This is important," Penny replied, walking past him into the apartment, not bothering for an invitation in. She never did, but then, they rarely seemed to mind.

Sheldon sighed and shut the door behind Penny before moving to his customary position on the end of the couch. "Oh, very well," he replied in a clipped voice, his irritation apparent. "but please be quick about it."

Penn glanced around the living room, noticing the absence of the shorter of her neighbors. "Where's Leonard?"

"He has opted to spend the night with a lady friend," Sheldon answered disinterestedly. Penny raised an eyebrow. Did Leonard have a new girlfriend? Good for him! She opened her mouth to press for details, then thought better of it as she recalled her original reason for coming over.

She shifted uncomfortably, wondering how to phrase her question. It was a bit embarrassing to ask, really. Hey Sheldon, how come guys suddenly run screaming every time I try to get some? She rolled her eyes at her inner cynic and sat down on the couch beside her neighbor. "Here's the thing." She pursed her lips as she thought about how to delicately phrase it. "It's been awhile since I've... fooled around." Sheldon stared blankly, and Penny frowned. "You know, gotten some?"

"Some what?"

Penny sighed. "Sex, Sheldon."

"Oh." He spent a moment processing this information before his eyebrows drew together. "Penny, are you propositioning me?"

Penny blinked. "What? No!" She shook her head in disbelief. "Wow. No."

Sheldon stared expressionlessly. "They why are you telling me this?"

Penny ran a hand through her hair. Maybe I should just wait and ask Leonard, she thought. But then, Leonard would probably try and use the situation to get her to have sex with him, and at this point, she wasn't sure she'd turn him down. No, it was better to ask Sheldon, she decided. "The last two nights, I went out to try and pick up a date."

Sheldon nodded. "Hooking up, I believe, is the term for that, is it not?"

"Yeah. Not really relevant." Penny took a deep breath. "The thing is..." Crap, this was awkward, even if it was Sheldon she was talking to. Maybe especially because it was Sheldon she was talking to. She wasn't really sure. How was she supposed to explain that she'd inexplicably become the most undesirable woman on the planet? A wave of self-loathing washed over the young woman, and she buried her head in her hands as she began to cry. "I don't know what happened," she sobbed. "Every time I even tried to talk to a guy, he'd freak out! I feel like some kind of mutant." When Sheldon didn't respond, she looked up, only to find the tall man staring at her with an odd, tense look on his face. "Sheldon?" she sniffled.

"Penny." She glanced up sharply, alarmed by the harsh tone of his voice. It was one she had heard very often from men – but never from him.

"Y-yeah?" she stammered, subconsciously standing up as he rose from his place on the couch. His face had an expression that was somewhere between pain and panic, and a sickening feeling washed over Penny as she realized with horror that she recognized the look on his face – it was the same thing those guys she'd tried to hook up with had gotten. Oh no, she inwardly moaned. Not him too!

He winced as she spoke, and Penny gaped as he balled his hands into fists. "You need to stop talking, now."

The pretty blonde blinked, taken aback by the command. The authoritative tone combined with his body language was really unnerving her. Still, he hadn't run away, which was better than any of the other guys had done. Maybe she'd be able to find out this time what the heck was going on. "Stop talking?" she questioned. Was this happening because she was talking? She didn't think she'd said anything weird, or that her voice had changed – how could talking do... whatever this was to anyone? "I don't understand," she mumbled, frowning.

Sheldon took a step towards her, his eyes blazing with a frightening intensity, and Penny backed up again, absurdly afraid that he was going to do something to her. It was a ridiculous notion, but then, she'd never seen him act like this before. She had no idea what to make of it. "I don't understand this either," he spat out. "But every time I hear your voice..." He hesitated, and for a fleeting moment, Penny thought he looked extremely embarrassed. But then the moment passed, and his face returned to an expression of distress. "It doesn't make any sense," he muttered, staring at the floor. Penny realized that he was talking more to himself than to her. Then, his head swung up, and he stared at her. "Penny, you're doing something to me that I don't think I can handle for very long," he stated with a seriousness that worried Penny. "You need to leave."

Penny fidgeted nervously. She'd never seen Sheldon in such a bad state before, which normally would have been enough to incline her to do as he said without question. But at the same time, she had no idea what was getting to him, and as she thought about the unusual encounters she'd had with other men the past few days, she decided that she had to find out, certain that his behavior was somehow related. "What am I doing to you?" she asked softly.

Sheldon actually groaned aloud this time. "Your voice," he whispered, tensing up. "It's making me..." He swallowed and looked away. "I do not want to say."

Penny's eyes narrowed, and she moved towards Sheldon, whose eyes grew wider with each step she took, until she was less than a foot away from the tall physicist. "I want you to say," she hissed into his ear.

Sheldon let out a strangled noise and sank back into his seat, eyes twitching madly. He slipped his hands under his legs and gritted his teeth, refusing to look at Penny. "N-no," he choked out.

Somewhere in the back of her mind, Penny knew that whatever she was doing to Sheldon was obviously unpleasant. And even though she had no idea what was going on, it was pretty clear at this point that it really was her doing this to him. But she just couldn't push back her need to know what was happening to him, and how she was doing it. "Sheldon!" she barked out. "What the hell is going on?"

The now-shaking scientist drew in a gasp. "S-stop," he whimpered. "You're m-making me..." he trailed off, face bright red. "Well, look!"

Penny turned her head, confused, until she realized that he was gesturing to his lap, and she saw very clear evidence of exactly what she was doing to him. "What the hell?" she whispered. Then she looked back at Sheldon's face, and in a louder voice, stated accusingly, "You're turned on by this!"

Sheldon flinched away. "Not by choice," he replied in a strained voice. "Whenever you speak, it's like... like I'm being... t-touched." He hunched over, refusing to meet Penny's mortified stare. "Please leave," he implored, his voice rising. "I've never.. Nngh! Never felt... like this before. I... I don't know if I can control myself."

Penny stared in utter disbelief at her neighbor. It was absurd, unthinkable, that she could have this sort of effect on anyone just by speaking, least of all Sheldon Cooper. And yet, she could hardly deny it – not while, just in front of her, was the living evidence, digging his fingernails into the sofa as he held back quiet moans. But the worst of it was not, Penny realized with mild horror, the fact that Sheldon appeared to be on the verge of orgasm. No, much worse was the fact that it was kind of turning her on. You're drunk with power, she assured herself. It's just the fact that you can do this to someone. It's got nothing to do with Sheldon. Penny figured that, were he in his normal state, Sheldon would have been able to rattle off some psychobabble explanation from Freud explaining why she was aroused by the situation. The only problem was that it didn't really matter why it was happening – the fact was she was horny and she had not had sex in months, and she was currently in the same room as a man who appeared ready to burst if he didn't get some, himself. As she watched Sheldon squirm, Penny was aghast to realize that with each passing moment, she became more and more tempted to jump him then and there.

"Crap," Penny whispered. Unfortunately, in her own turmoil, she'd forgotten what Sheldon's trigger was. It wasn't until his head shot up and he lunged towards her that she remembered that her voice was responsible for his condition. She moved to clap a hand over her mouth, but Sheldon beat her to the punch, covering her lips with his own. There was a brief moment of terror as she found herself torn between total arousal and that fact that sleeping with him would totally fuck up her relationship with the nerdy genius forever. And then his tongue slipped into her mouth and Penny forgot why she'd ever objected to the idea in the first place.

The two tumbled down onto the couch, mouths tangled together as they made out. Penny found it easier to forget that it was Sheldon as he pressed against her with an urgency she'd seen in dozens of men before him. She slipped her left hand up his shirt, tracing shapes on his back as his hands gripped her waist. Her right hand grabbed the hem of his shirt, pulling it up. He pulled his hands from her hips long enough to help her pull the garment over his head, the second shirt underneath coming with it. Sheldon's thumbs slipped under Penny's jeans, and her own hands fell onto his now-bare chest, stroking the soft skin.

"Counter-clockwise or my chest hair mats," he mumbled against her lips, and for a brief moment, Penny recalled who she was with. But then his mouth fell onto her neck, and once more, Penny was lost in the moment, intoxicated by lust.

Long fingers quickly unbuttoned Penny's jeans, and she shimmied out of them until they pooled around her ankles, exposing a bright red lace thong. Sheldon's lips traveled further down Penny's body, tracing sloppy kisses down onto her shoulder. He pulled at the fabric of her top, trying to expose more skin as he kissed and bit her. Somewhere in the back of her mind, Penny found herself astonished by the geek's passionate aggression. While his clumsiness made his inexperience apparent, it was also clear that he was very much into what he was doing. It seemed that, like any other task he put his mind to, sex was something he approached with fierce intensity. Penny licked her lips and slid her hand into Sheldon's khaki pants, lightly gripping him through his underpants. She received a startled yelp in response, and the tall nerd arched his back.

"P-Penny!" he spluttered, jerking back as Penny's grip tightened. "Guh... No, w-we can't—!" The logical half of his mind had apparently managed to take control, although it was apparent that he was struggling to suppress his libido as he alternated between gibbering half-hearted protests and bucking against Penny's hand.

"We can," Penny purred, lips brushing her neighbor's ear as she spoke. Like magic, Sheldon's protests died, and he melted into her touch. Penny felt a surge of adrenaline as she realized the extent of this incredible ability of hers, and she removed her hand from Sheldon's trousers, fumbling with the zipper as she tried to pull them down. Larger hands closed over her own, helping her move the clothing, and within a few seconds, both of the lust-driven pair were in their underwear. The two ground against each other, and Penny pulled her neck away from Sheldon, kissing him again.

"Do it," she commanded between gulps of air as she yanked Sheldon's underwear down. Her own followed moments later. And for once, Penny did not at all have to explain herself, despite the vague command; Sheldon grunted as he thrust into her.

It was shockingly quick, but then, Sheldon had been nearly there before they even began. To his credit, he lasted long enough to get Penny there as well. However, as the pair panted on the couch, recovering from what either one could have accurately described as the most intense orgasm ever experienced, Penny's fuzzy mind drifted back into awareness, and she slowly realized what had just happened. She stared at Sheldon, half-draped over her as he sucked in lungfuls of air, and felt a sinking sensation. There was no way their friendship could return to normal after something like this.

Sheldon stirred, his breathing close to normal as he turned his head to face Penny. His eyes were dull and glossy, suggesting that he hadn't quite recovered yet. He slowly pulled himself up and stared blankly ahead as he mechanically redressed himself. Penny watched him carefully as she replaced her own clothing, anxiously wondering what was going through the man's head. But she didn't dare ask him – if there was anything she'd learned about Sheldon by now, it was that when something unexpected happened, he needed to be allowed to process it. And to call this unexpected was the understatement of the century.

Sheldon sat back down on the couch after he finished dressing himself, positioning himself carefully on the far end, just the same as any other time. He didn't look at Penny as she pulled her pants back over her thighs; it wasn't until she had finished dressing and begun staring at him that he turned and acknowledged her presence.

Silence hung heavily in the air, emphasizing the ultimate awkwardness of the situation as the two regarded each other. Penny desperately searched Sheldon's face for a sign of something, but he was totally unreadable. Finally, however, the silence was broken when Sheldon said softly, "I'll never see this couch the same way again."

Penny stared at him, unable to fathom his remark. Of all the things one could say at a time like this! Stunned by the ridiculousness of the comment, she did the only thing she could think to do: she laughed. A hesitant, terrified laugh that was only a laugh because she was afraid that otherwise, she would cry. After a few moments, her laughter was joined by a deeper voice. As Penny threw herself onto Sheldon, burying her face in his shirt, she knew that the moment they stopped laughing, they'd have to face the situation. But for now, there was nothing in the world except the hysterical cackling of two accidental lovers.