The Amphetamine Phenylethylamine Effect

– Stage 1 –

"Pheromones"

Dr Sheldon Cooper had never fully understood why females consciously covered their bodies in a poisonous mist of animal secretions and sickly-sweet alcoholic scents.

He looked out of the car window and up at the billboard Penny and he were passing by in her car. The advertising monstrosity could have been better used for showcasing the dates of the next Comic-Con, he thought, instead of the writhing nude bodies and twisted letters spelling 'Aphrodite' in bright pink.

Seeking the opinion of a female to settle his confusion, he turned to Penny. Her hair was wildly flicking about in the wind coming through the open window on her side, while her mouth was shaping the words to the song on the radio.

"Penny, I find myself in need of your female insight about certain matters that I do not understand."

Penny's eyes darted off of the road and to him for a moment, before they turned back and she sighed. "I'm not going to be discussing my 'cycle' with you again, Sheldon."

"Good, because I already know that it began three days ago. My memory is faultless."

Her mouth dropped open, before she simply shook her head at herself and ignored his reply.

Seeing that she had not discouraged him from his questioning, Sheldon continued. "I wondered whether you could enlighten me as to why women insist on buying perfume."

Penny frowned at the road. "To smell nice, Sheldon."

"Ah! But there is the root of my confusion! Perfumes do not 'smell nice,' as you say, and they consist of a variety of ingredients, all of which seem highly ridiculous – and some most definitely unsanitary – to cover oneself in."

She shrugged her shoulders at him, already looking like she was tired of his probing. "Things smell different to different people, sweetie. Not all of us have your Spidey senses."

He gave a short nod, accepting that not every human had the honed faculties and capacities he did, and continued on another line of questioning.

"I understand the way advertising works, going for the 'weak point,' as it were, and preying on the primitive desires of Homo sapiens, but I wonder whether this is a fruitless endeavour as the natural pheromones released from the human body generally predict the likelihood of coitus taking place."

Penny stared at the road for a moment, wide-eyed and brain obviously thinking away, before she shot Sheldon a quick and confused glance.

"Do you mean…why do people use perfume when natural scents are meant to be more attractive?"

Sheldon considered her simplified sentence for a moment, before concluding that it would suffice and giving her a nod.

"Well…" She tapped her fingers on the steering wheel in thought. "I suppose…not everyone has a very attractive scent, and those people feel the need to buy a fake one to make up for it… Oh, I don't know, Sheldon. Different people like different things. Can we drop it?"

He considered her for a moment. "Do you wear perfume, Penny?"

"No."

"Why not?"

"Because I think it's nicer not to. It overpowers."

Sheldon smiled, satisfied that there was at least one more sensible consumer in the world.

Penny quickly changed the subject before Sheldon could say anything more. "So, why couldn't Leonard take you home? You said he was busy – what's he up to?"

Sheldon gave a derisive snort and crossed his arms over his chest. "He's dabbling in interferometry for his current experiment. He's like a blindfolded monkey with a hammer – only less productive."

Penny frowned at Sheldon's insult, but he saw the twitch of her lips that indicated her desire to laugh. He postulated that it was her previous relationship with Leonard that dictated her sense of loyalty when it came to making fun of him and his research.

Their building suddenly came into view and Sheldon let out a relieved breath – the blinking check engine light on Penny's dash had been becoming harder and harder to ignore.

Penny pulled in and parked, turning off the engine and rolling up her open window, and Sheldon was suddenly assaulted by a scent.

It made him reel.

His head snapped towards Penny, who was innocently looking through her purse for the key to her apartment. Looking at her, his eyes caught a small stain on the apron of her Cheesecake Factory uniform.

"Penny…what's that?"

She looked down before rolling her eyes and throwing her hands up in the air. "Some jerk knocked me into a wall while I was carrying a tray to a table! Can you believe that? He didn't even say sorry!"

As she huffed in remembrance, Sheldon's brain seemed to…malfunction.

It was the White Chocolate Raspberry Truffle cheesecake special smudged on her apron – he could smell it – and while a part of his brain went wild at the knowledge that there was old dairy product staining her clothes, another part was completely blank because of it. That was his favourite Cheesecake Factory cheesecake.

There was another scent as well. He hadn't smelt it upon getting in the car when Penny picked him up at Caltech, most likely because she had the windows open when he got in, but in the enclosed and now-sealed space he could certainly identify it.

It was Penny. Pure Penny. It was fuzzy, complex, sweet and yet not too sweet – it reminded him of warmth and Halo nights when she would sit next to him on the couch in his and Leonard's apartment playing furiously.

He liked the smell – he liked it a lot.

"Sheldon? Sweetie?"

He looked up to find Penny at the passenger-side door, standing there with a confused smile on her face as she held it open for him.

"You okay?"

He paused for a moment, considering sitting in the car a moment longer to inhale the scent some more, before angrily shaking his head at himself and hurrying from the car.

"I'm fine. Car sickness. You're a terrible driver. You need to take a class. I'm going inside."

He shuffled off quickly, leaving a bemused Penny behind.