Philematology (n.) - the art or science of kissing.

Penny had been in the middle of undressing when she heard the customary knock to her apartment door: three knocks followed by her name, each act repeated thrice. On the first set of knocks she had managed to shuck off her skirt and panties, dropping them with the rest of her uniform that lay in a crumpled heap on her bedroom floor. On the second set of knocks she had run naked to her dresser and pulled out a pair of shorts and tank top. By the third set of knock she had already slipped the tank top over her head and was hopping towards the door, trying to snake her feet through the legs of the shorts.

"Almost there," she said aloud, mostly to herself, as she continued skipping forward.

In her frenzy to get dressed, though, Penny's toe got caught in the hem of the shorts and she went sprawling face-first onto the floor with a loud thud and oomph.

"Penny, are you all right?" came Sheldon's voice from the other side of the door. "Are you hurt?"

"Just my pride," Penny mumbled, pushing herself up onto her forearms. "Come on in, Sheldon. The door's open."

The lanky physicist had already opened the door by the time Penny scrambled to her feet, sans shorts and panties. It was Sheldon who was first to notice Penny's lack of clothing—with great dramatics.

"Good Lord, woman!" He quickly turned away, averting his eyes with a large hand. "Shall I come back at a better time, when you are decent?"

"Decent?" Penny repeated, perplexed, and placed both hands on her hips.

It was then that she felt the bareness of her own flesh against her palms and glanced down at her lower torso in shock. Holy crap on a cracker! She was naked! Cursing, she dropped to the floor to gather her shorts and pulled them on with surprising speed.

"It's okay, Sheldon," she said breathlessly. "You can look now."

Sheldon lowered his hand and hazarded a glance; blinking once, he pursed his lips together and gave her a customary salutation, "Hello."

"Yeah, hey, Sheldon," Penny said with a sigh, snapping out the waistband of her shorts and smoothing them down her hips. "What's up, buttercup?"

Sheldon watched her fingers for a moment and wrinkled his brow before turning to close the door behind him. Walking over to the sofa, he hesitantly took a seat and tested out the cushion until he was comfortable.

"I would like to enlist your aid as a 'teacher'," he began, curling his index and middle fingers on both hands and lifting them in the air.

"How can I 'help' you, Sheldon?" Penny asked, mimicking Sheldon's air quotation marks, before taking the seat next to him. "'Cause Lord knows that I am only one woman."

Sheldon snapped his head back in tandem and glared at Penny, not bothering to enquire what exactly she was talking about. He was quite certain he wouldn't be pleased to hear her answer.

"Yes, colourful exchanges asides," he began blandly, placing his hands on his lap, "I would still like an affirmative or a negative on the proposal for your assistance."

Penny leaned back, knowing full-well what an endeavour such as aiding Sheldon would entail and how badly it would most likely end—for her. However, she was very curious about the matter as Sheldon had never asked her to teach him something, especially something that she believed herself to be good at. Plus, in the past he had agreed to teach her the fundamentals of Physics when she had asked him to, so it was only fair to return the favour—as long as it was feasible. She wasn't going to rent out her uterus or supply him with a healthy ovum. She had to have her boundaries.

"Tell me your proposal," Penny said evenly, eyeing Sheldon somewhat warily, "and then I'll let you know if I'm willing to help or not."

Sheldon nodded briefly; a small, boyish smile touched his lips. "Very well," he agreed, seemingly impressed that she had added a condition that she be informed of the facts before blindly agreeing to supply him with a favour. "I should preface this proposal with some context then."

Penny let out a groan and sank back into the sofa. Prefaces from Sheldon, like his summaries, were not exactly known for their brevity or understandability (at least for Penny).

"You see," he began with a finger poised in the air, making as though he was about to give some tedious lecture. That was, of course, before he noticed the unimpressed look Penny was giving him—a murderous glare, really—and Sheldon decided to shift gears and try for a more laconic response. "Amy's mother invited me to dinner, as she believes that her daughter is a relationship with me."

Penny blinked nonplussed. "But aren't you?"

"Technically, yes," Sheldon answered, his left eyelid twitching uncontrollably. "She is my friend, and she is a girl ..."

"Right, right," Penny said with a dismissive wave of her hand. "So what do you need me for—to teach, that is?"

Sheldon fidgeted in his seat for a moment before nervously darting his tongue along his lower lip and glancing away.

"Amy suggested that we try kissing," he said, failing to meet Penny's gaze. "To show her mother that we, in fact, have affection for one another and are, as you often say, boyfriend and girlfriend." He glanced up, the tendons on his neck standing out. "Engaging in coitus, if you will."

Penny blanched before choking on her own phlegm, glad that she hadn't been drinking something or it would be all over Sheldon's face right now. After a good twenty seconds of coughing, Penny cleared her throat and opened her mouth to say something before going mute and pulling a face that suggested she was quite uncomfortable the idea of Sheldon having 'coitus' with Amy. The mental image, in fact, made her shudder uncontrollably and she started coughing again.

"Sorry," Sheldon said, correcting himself with a smile as he reached forward to pat Penny's back. "I meant intercourse."

Penny nodded and leaned forward as Sheldon continued patting her back while she coughed. After a moment, she righted herself and began dabbing at her watery eyes. Coitus or intercourse—it just didn't sound right coming from Sheldon's mouth.

"So, you two haven't kissed yet?" Penny asked, trying to regard Sheldon with earnest sincerity.

"No." He tilted his head to the side. "We did try holding hands once, though."

"Oh?" Penny sat up in her seat, her curiosity piqued. "How was that?"

Sheldon shrugged. "I was indifferent to the whole matter."

Penny snorted. "Of course you were." She rolled her tongue along the inside of her cheek and regarded Sheldon carefully. "So, you want to learn kissing, then—and you want me to teach you?"

Sheldon nodded; his blue eyes were keen and serious. "Yes, I would like to learn from an expert."

"An expert?"

"You have had thirty-one sexual partners, have you not—or has the number gone up?"

Penny chewed on her lower lip and looked away, tautly grasping the arm of the sofa. Sometimes it took all her willpower not to punch Sheldon in the face.

"I assume that you have some working knowledge of kissing," Sheldon continued, "unless there was never any kissing involved—"

"Okay, Sheldon," Penny interrupted, turning to meet his innocent blue gaze with narrowed green eyes. "Okay." She then let out a sigh of defeat, allowing her features to relax. "I'll help you. I'll teach you how to—how to kiss."

Her words tasted like sand in her mouth, and she found it hard to believe that she was even agreeing to do this. But Sheldon had helped her out on more than one occasion—much more than one—and she felt as though she owed him as a friend. It wouldn't hurt to help him—would it?

"Thank you, Penny."

He was giving her that small, boyish smile of his again, and she couldn't help but return it before rolling her eyes and letting out a laboured sigh.

"Lord knows I'm going to regret this," she mumbled to herself, before sitting upright and squaring her shoulders back to look directly into his eyes. "Sheldon—" she reached out to touch his shoulder "—have you ever kissed a girl before?"

Sheldon bent his head and examined his hands while giving a slight shake of his head, suddenly shy.

"My mom and my memaw," he answered, and then glanced up to meet Penny's gaze with a lick of his lips, "but I don't think they count."

Penny smiled and squeezed his shoulder. "No, sweetie—no they don't."

She dropped her hand and inched closer towards him, watching him recoil slightly and sit up even straighter in his seat—if that were even physically possible.

"Since this will be your first kiss and you want to kiss Amy in front of her mother—" she reached out to take Sheldon's hands "—we'll try something simple and chaste, okay?"

"Good," Sheldon said with a slight drawl, his eyes darting from side to side. "I really don't want to 'suck face', as they say." He licked his lips nervously again and swallowed hard, his fingers taut in her hands. "No offence."

Penny's smile widened. "None taken."

She felt like they had already made progress, as he hadn't removed his hands from hers. However, he was stiff as a starched shirt, and she really needed him to loosen up in order for her to teach him something that required a level of intimacy. Of course Penny just needed to teach Sheldon how to kiss without throwing up or sanitising his mouth directly after.

"Sheldon, you need to relax," she said in what she hoped was a calming voice.

Sheldon's hands were cool in hers, and soft. In fact Penny was struck by how soft and smooth they were—and long, like pianist's hands. After a moment his hands finally went slack in hers and the rest of his body followed suit. Eventually, he was fully relaxed—or at least as relaxed as Sheldon Cooper could ever be without being asleep or unconscious.

"Now shut your eyes," Penny ordered softly, bringing a hand up to his shoulder, causing him to flinch.

"Penny," Sheldon began in a strained voice, his eyes wide open, "I do not see how I will learn anything with my eyes closed."

The tips of her fingers rested on his neck, and she could feel the bulging of his tendons and the ripples of his skin as he swallowed. She felt his heartbeat too; it was rapid, like her own.

"It's more of an act you feel out rather than emulate," she informed, licking her own lips in nervousness.

Wait, why was she nervous?

"Like instinct?" Sheldon's blue eyes rested on her lips for a fraction of a second.

"Exactly." Penny could feel her cheeks flush with heat. "Just feel my lips against yours and react to them—" she offered him a sheepish grin "—and not by pulling away."

Her other hand reached up to touch his neck and he blenched, his face twitching in discomfort at her close proximity.

"Just relax and breathe," she encouraged, slowly travelling her hands up to his jaw to cup his cheeks. "Lean in and close your eyes, and do what I do."

"You said this isn't about emulating," Sheldon countered in a whisper, his blue eyes meeting hers.

"It isn't," Penny said, unconsciously tracing her thumb along his cheeks. "It's about reaction: you emulate the action of kissing, but in your own way." She tilted her head. "Do you get it?"

Sheldon shook his head. "No, but let's experiment—" his gaze travelled to her lips before he closed his eyes "—and then I can make a hypothesis."

Penny nodded and then closed her eyes as well, leaning forward and hoping that he was doing the same. She met his mouth and firmly pressed hers lips against his, feeling how soft and full they were. Parting her lips, she felt his part with hers. She then pulled his top lip between hers, letting it slide along her lower lip before she switched, taking his bottom lip into her mouth and nipping it gently. She did not slide her tongue inside, fearing his reaction. Sheldon, although he didn't initiate anything, didn't stiffen against her either like she had anticipated. Instead he had sort of melted into her; his lips were warm and inviting.

Penny opened her eyes for a second, just to look at his face. His eyes were closed—his long, black lashes tickling against the apples of her cheeks—and then they fluttered open, as if realising that the kiss had ended. Blue eyes met green, and they both drew back, lips parted and swollen.

It was a brief kiss to be sure, but it wasn't exactly chaste either. It wasn't what she had wanted to teach him, what she had expected to teach him. She had wanted to just press their lips together and push out, getting him used to the sensation, but her instincts had got the best of her.

Damn her instincts!

"Did I do it right?" Sheldon asked curiously, stirring Penny from her reverie.

"Uh yup," she said numbly, popping the P before she shook her head and blinked rapidly. Blushing, she lowered her hands from his face. "It was, uh, good for your first time, Sheldon."

Sheldon's face instantly lit up. "Thank you, Penny." He folded his hands together and smiled proudly, like the time he had discovered how to successfully employ sarcasm. "Do you want to try again?"

Penny's mouth dropped open in shock; she was trying to comprehend what exactly Sheldon was proposing. He wanted to kiss her—again? No, this wasn't going to bode well. He was her friend. She didn't want to give him the wrong impression.

"Sure," she said, leaning forward to capture his lips with hers again.

Dammit! Her body really needed to start listening to her brain.

-x-