Enjoy! TBBT isn't mine :)

She had truly been prepared to talk with Penn, she really had. With Lenore's somewhat envious approval in her pocket, Shelby had quickly gotten dressed in her Sunday clothes and hurried to get ready, before nearly dashing across the hall to knock on Penn's door. As her customary knocking habit rattled out, she had forced herself to breathe and remain calm, determined to be in control of today's conversation.

Then he opened his door nearly naked. Shelby saw his welcoming grin and then her eyes were drawn irresistibly down. He looked just as good as he did yesterday, wrapped in a towel, except now his hair was tousled and damp, his face slightly scruffy as he hadn't shaved yet.

Her eyes moved slowly over the planes of his chest, her heart stuttering, her breathing not nearly as controlled as it had been a moment before. He was standing close enough to touch and she nearly had to tuck her hands into her pockets to keep from reaching her tentative fingers out to find out what the tan skin of Penn's torso felt like under it's smattering of blond hair.

He invited her in and she had moved in a daze to the couch, sitting slowly, trying to refocus herself as she heard him disappear into the bedroom behind her. Her eyes opened a little wider as she looked around the room, feeling her toes curl inside her shoes.

Everything is Everywhere, she thought in horrified alarm. She couldn't understand how Penn had even managed to sleep with the knowledge of these boxes in his mind. She knew that she would have to do something about this, the pressure on her brain brought by this scattered chaos would be too much for her to bear. First the experiment, then this mess, she thought, bargaining with herself.

She whirled around when she heard Penn emerge from his bedroom, dressed in a pair of long blue surf shorts and a grey t-shirt. He smiled at her and she felt compelled to return his smile. When he sat on the couch, he purposefully seemed to leave a cushion of space between them.

"So," he began, running a hand through his rumpled, sun-kissed hair, "I'm really glad you came by this morning." Shelby watched his hands and then nodded at him, rearranging herself a little on the couch.

"I have obviously come to discuss your proposition from last night," Shelby stated, looking from her hands, curled together in her lap, up to his face, and then back to her hands again. Penn nodded encouragingly at her.

"I find, against my better judgement, that I am physically attracted to you, Penn. This is a new experience for me, and I am still not fully certain why you evoke this in me, although I will endeavor to find out," Shelby explained, turning in her seat to look over at Penn. His face was still, and she could almost see his mind trying to get ahead of itself, sifting through her words, looking for a yes or a no.

"On the basis of that attraction, I find that I am not opposed to the idea of experimenting with a physical relationship, with you," she clarified for him.

Penn grinned at that and slid a little closer to her. Shelby leaned back against the arm of the couch, her heart fluttering as she tried to move away. She held a hand up between them and had to grit her teeth when she felt her hand connect with his chest.

"Wait," she ordered, her mind fumbling along, tripping over words. Her fingers skittered across the soft cotton of his shirt, hinting at the firm muscle beneath.

"Penn, please let me finish," she told him. He nodded, and leaned back a little, raising an eyebrow at her. Shelby let her hand drop down into her lap, trying to ignore the itch her fingers felt, wanting to touch him again.

"There must of course be rules to this experiment," she started. Penn smiled and nodded and Shelby breathed a little easier, glad that his reaction to the notion of rules was positive, that she wasn't asking anything ridiculous.

"Rule 1 - we will move at my pace, if that is too slow for you, then I'm afraid the experiment will come to an immediate end. Rule 2 - if I am uncomfortable with something and do not wish to partake in that particular activity, then it does not and will not happen."

Penn smiled at her and replied, "Of course, Shelby, I'm not saying I want us to fool around and do everything in one afternoon. I want you to be happy. I want this to work. I think we'd make a pretty awesome team." Penn's green eyes held hers and Shelby found herself having to focus hard to respond. Come on, Cooper, stay in the game.

"Rule 3 - I am not looking for a romantic relationship, please do not try to turn this into one. I am approaching this from a purely scientific standpoint," Shelby added. Penn gaped at her for a moment. He was slowly shaking his head and Shelby felt her heart sink; she hadn't anticipated an argument this early.

"Shelby," he started, his voice amused, "We don't have to immediately become a couple, but this will be a relationship of sorts, and part of the fun of a physical relationship is the lead up to the really fun moments. Like, holding hands in public, kissing on dates, hugging as a way of saying hello. This won't be happening in a science lab, it's going to be the full meal deal for you to truly experience it properly."

Penn placed his palms flat in his knees, looking at her expectantly. Shelby got to her feet, to pace, as she typically did when she was perturbed, but found his apartment in poor shape for pacing.

"There is not enough space in here," she said, shooting him a pointed look. Penn got to his feet and stood next to her, gently and slowly taking her hands in his and pulling her back to the couch, to sit down.

"Chill out, Shelby, take a seat and let's finish discussing this," he said soothingly, as she sat next to him. She slowly pulled her hands from his grasp, her breath catching in her throat when he gripped her fingers for a moment before letting her go. She crossed her arms across her chest and cleared her throat to continue.

"I understand what you are saying, I had no intention of us carrying on a physical relationship in a science lab. I don't imagine that would be comfortable or conducive to sexual interaction," Shelby explained, nodding at him, and Penn chuckled. He leaned back against the arm on his side of the couch and opened his mouth to talk, but Shelby held a finger up to stop him.

"Let me finish, please," she said quietly, her jaw tight, "This topic is very difficult for me and I just need to explain everything to you, please." Penn nodded and buried his smile, waving a hand at her to continue.

"Rule 4 - Cleanliness is paramount. We will clean our hands, brush our teeth and shower whenever possible before our interactions, to ensure that a minimal amount of germs are spread." Shelby was dead serious and her brow drew down when she saw his lips twitch in amusement.

Penn cleared his throat and told her, "Sorry, absolutely, whenever possible, got it." Shelby nodded at him slowly and ticked off another point on her fingers.

"Rule 5..." Shelby trailed off, not sure what to say next. She had never felt so stupid in her life. She felt like her IQ dropped dozens of points simply by being in the same room as this man, she was so unable to think straight. Penn smiled warmly at her, his eyes bright. He leaned towards her.

"I agree to everything," he said, his voice low. Shelby sat still as he slowly moved an arm behind her shoulders, wrapping it around her, his other hand snaking up slowly into her hair. She watched him bend his face to hers, her breath strangled, her heart thumping audibly. Her body was torn between melting at his warm, firm touch and twitching at the unfamiliar contact. He closed his eyes as his lips connected with hers and she slowly tried to give herself over to the moment, surrendering control to him, a monumental task for herself.

This kiss was less frantic than last night's had been. He moved more slowly, the hand on her shoulder blades slowly pressing her towards him. Her face tilted up towards him, his other hand wrapped languidly in her hair, deliciously clenching and unclenching handfuls of it, as if it were the finest silk.

His lips on hers were warm, soft, and pleasant. Shelby knew she should be analyzing the moment a little more closely, for science. But she couldn't, instead she moved one of her hands up to grasp lightly at his bicep, and the other hand moved slowly up to rest on his collarbone, gently. Penn pressed her a little more firmly towards himself, her back arching slightly with the movement, and Shelby felt the tip of his tongue press gently against her lips.

Though it was not unpleasant, Shelby felt like she was in overload and broke off the kiss, leaning away from him, her hands pushing herself off of him.

"How was that?" Penn finally asked her, his voice slightly haggard. Shelby looked over at him, aware that the warmth in her face meant she was likely blushing. She nodded slowly at him as she swallowed hard, the look in his eyes making it hard to breath for a moment.

"Fascinating," she managed to answer, and that seemed to break the hazy spell because Penn started to laugh, very hard. He leaned in and gave her a quick kiss on the lips and chuckled.

"That's the first 'fascinating' I've ever gotten," he chuckled, squeezing her shoulder with one large hand before sitting back on his side of the couch. Shelby smiled helplessly, simply because he was. Looking around the room to try and calm her thundering heart Shelby felt her lips curl at the sight of so much disorder. She whirled back to Penn.

"Are you going to fix this today?" She said, waving a hand at the apartment around them. Penn nodded and then shrugged, a smirk on his face, before saying, "Maybe? Probably?" Shelby got to her feet and he seemed to rethink his answer. "Yes?" He offered.

"In return for this experiment, you will of course be prepared to accommodate my very specific likes, dislikes and interests in all other facets of life," she said clearly andlooked down at him, her hands clasped behind her back. Penn nodded, his face wary, but still amused.

"We will clean this now, I will help, you will listen, otherwise I cannot be in this apartment anymore, the mess is literally cluttering my mind," Shelby told him. Penn got to his feet and nodded, saluting her at the same time.

"Aye aye, Captain," he teased. Shelby let a small smile play across her lips as she turned to the first box, one by their feet.

"I'm not touching that box, it is filthy, open it and tell me what is in there and I'll tell you where it should go."

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Penn was entranced watching her mind work. She looked at the contents of each box with studied concentration for a minute or two and then began pointing at various hooks, shelves and sections of his apartment, explaining specifically which method of display or organization made the most sense. It was just unpacking boxes, but her brilliant mind was still very evident and he surprised himself by finding that as much of a turn-on as everything else about her.

He played back their kiss on the couch, while he carefully broke down emptied boxes, as per her instructions. Shelby's hair was so lovely, thick and soft, he had wanted to bury his face in it, to feel it rub all over his skin. The hand he had pressed to her back had felt her twitching muscles, the delicacy of her shoulder blades, and while pressing her towards himself, he had felt her bend willingly, almost eagerly.

He had forced himself to keep the kiss gentle, steady and slow, despite his baser urges. Urges that wanted to clutch her to his chest, tear off her clothes and have her in the bedroom, immediately.

He glanced up and looked across the room at Shelby. She was standing on a chair, carefully placing some small knick knacks his mother had sent him on the top shelf of his tall bookshelf. He watched her body stretched up, as her arms reached above her head, positioning each item just so.

His eyes were drawn to the small sliver of skin that appeared when her shirts lifted up from the waist of her pants. That peek of her smooth stomach had him moving silently, as if in a trance, across the room to her. He stood behind her and reached a hand up to gently trace the exposed section of skin. Shelby jumped a little and looked down at him, startled.

"Is this ok?" He whispered, his hand moving lightly along her side and she swallowed and nodded. His palm rested flat on her stomach, and then darted lightly under the bottom of the shirt. Her skin was smooth, her stomach flat, firm but yielding. He traced a line across her stomach, feeling her skin goose bump.

His palm passed over her navel before traveling across the dip of her waist, onto her back. Penn let his fingers move slowly along the skin just above her pants, stopping at the centre of her back. He began to trace his fingers upwards, feeling them bump slowly up the faint indents of her spine.

He marvelled at such perfect skin, at her delicate but deeply sensual figure, he moved his other hand to her side and, gripping her hips from each side, he pulled her towards him, pressing her body to his, so his head rested lightly on her chest. He pulled her further towards himself, stepping back from the chair and lifting her easily to the floor.

Shelby's hands fluttered to his shoulders, where she rested them, as he slowly put her down, allowing their bodies to skim along one another. When her feet were flat on the ground, her hands gripped his shoulders, and she turned her face up to his, her eyes hazy, wondering and wide.

He leaned down and kissed her forehead, then her nose, then pressed a kiss to her mouth, his hands tracing lightly up her sides, from her hips, to her ribcage, to her shoulders, to her neck, to finally cup her face. He pulled back from the kiss and saw how dilated her pupils were. They stared at each other for a long moment.

When she finally spoke her voice was rasping, her breath slightly ragged, but the small smile of stunned pleasure on her face let him know she was very happy. "That's enough for now," she said softly, but firmly.

Penn released her and continued to stare at her flushed face. She licked her lips and added, quietly yet forcefully, "Get back to work, it's awful in here."