A/N: I just had to write this little thing after watching S11E13 (The Solo Oscillation). I used two lines of dialogue from the show, and then it just becomes a continuation of that scene. More notes at the end.

Disclaimer: I don't own these two wonderful characters or anything related to The Big Bang Theory. I just like to play in this sandbox.

Leonard smiled at Penny's response. "That's cute, but you can't have knots in more than four dimensions." He wondered why Sheldon hadn't told her that, unless she'd made up her answer just now.

"Mm, you can if you consider them sheets," Penny responded, a little laugh at the end. She slapped him on his upper back as if he was the one not knowing anything about science. "Good night."

The thing was, her answer made perfect sense. Sheets would definitely get around that problem and, topologically speaking, would provide tons of other possibilities. He glanced at Amy, who seemed as dumbfounded as he was at the unlikely insight. Obviously, Penny had not come up with this idea, but it was very likely she had mentioned knots to Sheldon, which had somehow triggered his friend's brain into high gear and provide the sheet solution.

He looked back down the hall, just in time to see his wife's bum disappear around the corner. "I'm sorry, Amy, but I need you to go back to Sheldon." He ignored her smirk, and gave a shrug to her inquiry about cleaning up the remainder of the popsicle sticks. "I'll get them." Later. Much later, he hoped. He rushed Amy out of the apartment, locking the door behind her, and made his way to their bedroom.

Penny had put on her fake glasses, instantly transforming her into the sexiest scientist on the planet. He still hadn't figured out why the glasses made her look so much hotter than she already was. If anything, the glasses should make her seem less attractive, as they partially obscured her eyes. They weren't exactly the most stylish pair of glasses either, but somehow they just complimented her natural beauty.

It took him a couple of seconds to realize she was looking back and smiling at him as he simply stood there, taking in her appearance. Even through the glasses he could see her love for him. Despite their frequent banter in front of their friends, the regular claims he'd simply wore her down, when it was just the two of them, the fact that Penny truly loved him became obvious to him. She never hid it from him when it was just the two of them.

Leonard knew she wasn't ashamed of having ended up with him, it was just how they had chosen to portray their relationship towards their friends. Not that either one believed their friends were fooled, but Leonard enjoyed the way Penny playfully played their relationship down. It wasn't with malice, and almost always was accompanied by a look or quick touch that told the other they really didn't mean what had just been said.

He did the same to her, emphasizing her dumb blond routine; she wasn't a dumb blond, and she knew she wasn't some airhead. She would, however, happily pretend to be, giving Leonard something to make fun about toward their friends. Like her choosing to try and make a boat out of the newspaper, giving him an opening to mock her dislike of reading. Penny had no aversion to reading. On the contrary, she was an avid reader and not the glossy magazines, but actual, often thick, books.

"You know," Penny said contemplatively, pulling him from his inner thoughts. "Topologically speaking, sheets have a lot of possibilities."

Obviously those had been Sheldon's words, but with the glasses on, Leonard could honestly believe those were her own thoughts.

She patted the bedding. "Maybe we should explore some of those possibilities?"

Cheesy, but damn, having Penny uttering some scientific innuendo while wearing glasses was simply irresistible.

# # #

Penny had removed her sweater, jeans and bra. Not that Leonard needed the visual right now; her glasses, combined with the rudimentary scientific knowledge she'd gathered so far proved enough of a turn on to her husband. However, she could use a little extra, and she knew the perfect way. "Leonard, could you explain the sheet thing? I didn't really get any of that."

He was confused, not entirely sure why she asked him to explain something at this exact moment.

"Because my hair cells quiver when you speak to me." She hid the grin at the obvious increase in lust from him. Asking Bernadette to give her some scienc-y sexual innuendos seemed to have paid off already. After a couple of seconds he began to explain the concept of strings as sheets, getting some paper and a pencil to draw stuff out.

She listened intently, not so much to the words like she had when Sheldon explained string theory - of which she understood very little - but to his voice, the confidence as he spoke passionately about the subject. That was the Leonard that turned her on the most: the confident physicist, no trace of the shyness and insecurities he almost always exhibited. That wasn't to say Leonard couldn't turn her on otherwise; he still did little sweet things for her, getting her a little present just because, and that was as much of a turn on as listening to his confidence.

And even though he was putting on a bit of weight, not living as healthy as he could, there was a most definite physical attraction. She loved the quiet weekends in, as Leonard would often wear a tight t-shirt. It didn't necessarily mean she'd drag him to bed to get it on, at least not immediately, but it was very nice eye-candy as far as Penny was concerned.

She reopened her eyes when it registered that Leonard had stopped talking, his eyes drawn to the girls. Realizing immediately her nipples were rock hard, she grinned, something he either didn't notice or chose to ignore. She moved forward, taking his writing pad and pencil to place it behind him, and moved to sit in his lap. She kissed him, not hungrily or demanding, just a simple kiss, full of love and affection.

She could feel his aroused state, and she moved out of his lap to stand in front of him. She bend forward and worked on removing his pants, Leonard helping her by toeing off his shoes. Tossing his pants on the floor, she immediately set to work on removing his open button-up shirt, throwing it in the direction of the pants. She paused for a second or two, admiring his biceps, before she reached for the hem of the t-shirt. With practiced ease she removed it without upsetting his glasses, and the t-shirt landed on the floor moments later.

She started removing her own panties, making sure to do it slowly, turning slightly so he had a good look at her ass as she wiggled it while removing the last piece of clothing. She smiled as he told her she was so hot and bend forward to place a kiss on his lips. "Do I still denature your proteins," she whispered in his ear.

It took a good ten seconds before Leonard could utter a confirming "uh huh." Penny leaned forward, but instead of kissing him, she leaned past him to grab the writing pad and pencil. "I want to write down a question for you," she said, sitting beside him, but angled so that he couldn't see. With great concentration she began writing down the chemical formula she'd spend almost a week memorizing. Looking it over once more, she felt fairly confident it was correct, and she wrote the words "will we be" above the formula, before turning it over and show it to her husband.

When he chuckled and replied he certainly hoped so, she let out a relieved sigh. "I wasn't quite sure I got it right. Or if Bernie hadn't played a cruel joke."

He said it was definitely correct, real, and he'd buy her t-shirt with the formula on it. She broke of his explanation of the mineral being first discovered in the town of Cummington, by hungrily attacking his lips. She was more than ready for him and she wanted him to know she was. Not that she doubted for a second he hadn't realized it already, he knew her and her tell too well to be oblivious of her level of arousal.

Realizing Leonard's underwear was still in the way, she abruptly broke off the kiss, jumping off the bed an began removing the offending article of clothing. Leonard lifted his bum by leaning on his hands, and Penny took a brief second looking at his biceps working. She quickly yanked it off completely, throwing it on the floor. She did the same with the writing pad and jumped back on the bed.

She pushed him backwards onto the bed and, without pausing for the briefest of moments, sank down on his hard member. God, she loved the feeling of him sliding deep inside her. She saw surprise in his eyes, and Penny grinned. "Just wanting to see if we could find our position without losing our momentum." She silenced his chuckle with another kiss.

A/N2: Yes, I'm a horrible person for ending it here. I may or may not add a second chapter, just to see if these two characters are able to disprove the Pauli Exclusion Principle, and actually occupy the same space at the same time.

I appropriated pretty much all the innuendos from the web, sometimes paraphrasing a little. I'm not a scientist, so bare with me as I try to give an (often overly simplified) explanation.

The hair cells detect movement caused by sound waves, causing them to move slightly. So, Penny was right.

Proteins, when heated up (or other forms of stress or compound), will lose their structure, or denature. Once again, Penny was right.

The chemical formula is for a mineral called Cummintonite. T-shirts are definitely available.

Lastly, the uncertainty principle states that you can only know where a particle is, or at what velocity it is traveling. So you can either find a location (position), but lose velocity (or momentum), or you know the velocity (you kept the momentum), but you have no location (position). Penny was really good at disproving this principle :)