She watched him sitting in his spot. Eating Chinese food; because it was Friday, of course. Meticulously he dipped each piece of diced-not-shredded broccoli in the good hot mustard before popping it delicately into his mouth. Damn he was the most irritating person she knew. He was arrogant, annoying, totally inflexible, with more stupid neurotic habits then anyone she'd ever met. So why was she developing this stupid crush on him? She knew the signs; learning his habits (every stupid neurotic one of them), appreciating every little almost-compliment he paid her more than the greatest praise from anyone else.

On some level she even knew why; he didn't seem to care about her at all. If asked he would probably reply that they were not friends so much as two people who's physical proximity had led to a certain understanding which made their continued company less grating then that of the average unknown person, or at least she imagined the explanation would be something equally academic and long winded. As Leonards mother had once observed her opinion of herself was way too reliant on what others thought of her; and she was used to people thinking about her a certain way. Guys liked her, they wanted her, they treated her nicely. She didn't try to take advantage of them, she didn't allow herself to become to huge headed about it, but she realised now she had become used to it. But Sheldon had never ever looked at her as anything more than an acquaintance. On an academic level he had acknowledged she was attractive, but he just didn't care. His friends thought he was completely uninterested in any sexual contact with anyone & she'd seen no indication to make her think otherwise. She knew she was doomed to disappointment in any feelings she developed relating to Dr Sheldon Cooper, yet why did she keep noticing him like this? Why did she try to prolong eye contact, why could the sight of that small half smile make her heart beat faster?

"Why are you looking at me?"

"I wasn't!"

"Yes you were. Why?"

"I want to do an experiment." The words were out and she tried to stop the slow blush rising up her cheeks through pure willpower.

"Oh!" His blue eyes lit up, eyebrows rising with interest; "What hypothesis are you looking to prove?"

"I can't tell you..." he stared at her, "because, ah, foreknowledge of the hypothesis will affect the results..."

"Ah the placebo effect! Very insightful Penny, I'm surprised you thought of that!"

Damn! He always made her feel so unbalanced. So stupid.

"So then... what is your experiment? If you're hoping to discover if I have any psychic abilities I regret to inform you that despite multiple well-designed experiments on my part I have failed to discover any. Although many super-hero abilities only display themselves after some kind of trigger or exposure to toxic materials, so feel free to do your own tests, although I doubt you will think of any angle I haven't already tested."

"I want to kiss you."

"What? No!"

"I need to, to test my hypothesis."

"No. I refuse. Is this some kind of social science experiment? Because you know the social sciences are subjective at best and pure hocus-pocus at worst."

"I need to see something. Please."

"Is this like when my mother had me tested to see if I was insane?" He looked so suspicious, eyes narrowed, lips pursed. He wasn't going to agree. But she needed to try. Needed to prove to herself once and for all that Sheldon was an enigma, nothing would ever happen between them, and she needed to get over it.

"No. Nothing like that. Please, I will tell you after what the results are."

"Can I read the paper?"

"Yes."

"If it is ever published will I be a co-author?"

"Sure, why not?"

As usual the sarcasm went over his head.

"Ok." He stood perfectly still, watching her. She stepped closer to him, still he didn't move. This was ridiculous, Sheldon was incapable of human emotion, but at least if she followed this through to the end she'd know, than she could get over this, she was sure.

She took another step closer, now she was looking up to meet his eyes, bright blue, she could feel his breath fan across her face as he breathed out. She put her arms around his waist and he rolled his eyes and sighed, but awkwardly he lifted his arms and after experimentally trying to put his arms around her waist, then resting his hands on her hips, eventually he settled rather uncomfortably with his hands on her shoulders. She leaned in and he bowed his head, she closed her eyes and their lips met, her heart beat fast against her ribs, her hands clenched his shirt at the back, his lips were stiff and unyielding against hers, she opened her eyes for a second, only to see him staring back at her, cold impassionate eyes watching. She pulled back; "Close your eyes Sheldon."

"Why? You didn't specify that perimeter."

"I'm specifying it now. Close your eyes." She leaned forward and was surprised when without further protests he closed his eyes and bent to kiss her. Again his unyielding lips pressed against hers, and then he stood perfectly still. She moved her mouth against his, allowing her lips to slide open, her tongue flicked out to run gently along his lower lip.

Immediately he pulled back "what are you doing?"

She sighed; "it's called kissing Sheldon."

"With your mouth open?"

"Yes."

"That's disgusting. Do you know how many bacteria live inside the human mouth?"

"Would you like me to use mouthwash?"

He stood for a second contemplating while Penny shook her head at his complete lack of understanding of blatant sarcasm. "Yes that would be acceptable. Provided you use our extras strength mouthwash, the recommended 30 mLs for the recommended 30 seconds, of course."

"Of course." She sighed and retired to the bathroom, feeling completely pathetic for taking this completely illogical crap, but at the same time determined to follow this through.

When she returned from the bathroom he was standing in the same position she'd left him in. She stepped up to him and again they awkwardly placed their arms around each other. Sheldon leaned down and pursed his lips, closing his eyes and she looked at him for a second before closing her own eyes and leaning in to touch her lips to his. She let her tongue probe his tightly pursed lips and they opened slightly. Her tongue entered his mouth, she felt his own tongue just behind his teeth. Her eyes flickered open for a second; his were squeezed tightly shut. Closing her eyes again she allowed her tongue to slide against his, then retreat back to trace his bottom lip, to her surprise his tongue followed hers, pressing into her mouth. He groaned as his arms slid down over her shoulders, pulling her closer to him, she fell back at the sudden pressure, feeling her back meet a bookcase behind her, he pushed hard against her and she felt the hard evidence of his arousal press into her stomach. Wow, Sheldon was human. One of his hands found the small of her back and he pulled her harder against him.

Shocked, she pulled away. His eyes opened to meet hers and she saw her own shock and confusion mirrored back at her before he looked away.