Sheldon stood back from his whiteboard and sighed. The formula was beautiful- balanced, coefficients factored, deltas in perfect order. The arcs brought to mind the motion of Penny's back when he…

Knocking stopped his reverie.

"Yes." Sheldon gave a quick glance to the front of his pants to ensure he was presentable. More and more he had to do that whenever he thought of Penny since the start of their liaisons The door opened and Penny came in.

"Hi." She said.

"Hello." His tone was puzzled. "What brings you here?"

Penny smiled a little and gave her head a brief shake. She stood in front of the whiteboard. "I really don't know." She admitted. Her eyes were the color of sun-dappled leaves not murky with lust.

Instinctively, Sheldon leaned in toward her, bracing himself on his left arm. Penny reached out and gently stroked his right arm. The arm that she was beginning to think of as hers. She had certainly made her claim to it clear enough. Sheldon bent down and placed a row of gentle kisses along her jaw. Penny leaned into them. A soft sigh escaped her; she could easily get used to Sheldon like this.

"Let me kiss you." Sheldon's voice was deep with need and longing. A man's voice.

Instead of answering, Penny ducked under his arms and ran to his desk. She hopped on, knocking over a pencil holder and a stapler. Pulling her skirt up higher on her thighs, Penny leaned back on her arms. That caused Sheldon's desk calendar to slide precariously to the edge and also toppled over his Mountain Dew. The green liquid trickled onto the floor and meandered across the desk.

"My work!" Sheldon cried, reaching over to right the bottle. He was there between her tanned thighs, her breasts pushed against his chest. His right hand had landed on her left leg when he leaned to grab the bottle. Penny gave a nip to the skin just covering his Adam's apple.

"Is the door locked?" He asked; she shook her head 'no'.

"Good." His mischievous grin appearing before he slid a finger into her and groaned at the moisture there. Penny did a sharp intake of breath as Sheldon tried to establish a rhythm. She reached down and pushed his middle finger into her as well. His eyes burned into her and she leaned back more to tilt her hips.

Sheldon's other hand traveled under her shirt to curve over her breast. His hands were magic. Long fingers, delicate wrists, slim forearms. Penny's arousal increased just thinking about them and she clenched her muscles around the fingers there.

"Angels and saints." Sheldon spluttered into the crook of her shoulder. He changed the angle of his hand, curling his amazing middle and index fingers. Penny panted audibly and clasped her legs around his waist.

"Penny, come for me." Sheldon's lips were dangerously close to hers. He increased the friction. Penny slid her hands under those damned double shirts. Her nails bit into the flesh of his shoulders. She became aware of the quiver in her thighs.

"Sheldon…it's…I'm…" He wrapped his other arm around her to pull her closer. Penny drew her nails down his back as Sheldon felt and caused the tremors to go through her.

When she had left, he surveyed the wreckage of his office. His flawless equation was smeared. All his pencils had disappeared into unknown corners of the room. His calendar had made the final leap to the floor during Penny's orgasm and now soaked up the Mountain Dew that coated the floor. The air smelled of sex . Sheldon ran his hand through his hair. He didn't even know how to begin to straighten this out.

"Do you need custodial services?" Howard leaned against the doorway.

"What are you doing here?" Sheldon demanded.

"I believe I have the same question but, since you asked first, I came to get you for lunch." He leveled his eyes at Sheldon. Howard didn't have to wait long. Under scrutiny, Sheldon's mouth began to twitch.

"Sheldon," Howard adopted an advisory tone, "if this a grad student, you're taking a terrible chance screwing around at work."

Sheldon picked up his calendar. It dripped onto his shoes. "Why do you automatically assume that I was engaged in some illicit tryst?"

"Hey, your words, not mine." Howard sniffed the air. "Furthermore, I can smell her. It's oddly familiar. Vanilla sugar. Probably from Bath and Body…" He suddenly stopped talking. Sheldon was glaring at him with such vitriol that even Howard was surprised his head hadn't exploded.

"Ooh!" The engineer hooted. "Ooh! No way! There's just no way. Except it all makes sense now." Howard rubbed his hands together. Sheldon looked about ready to faint. "So tell me, is she as delectable as I always fantasized she would be."

Raj stopped short when Howard came flying out of Sheldon's office followed by a half empty bottle of Mountain Dew.

XXXX

Sheldon checked his watch for the third time. He looked at his reflection in a store window, smoothing down his black shirt with the white chevron symbol and tugging at his long sleeved black undershirt. The absurdity of it all hit him. He should be home working on his next publication. The greatest mind of the twenty-first century was apparently on sabbatical and lesser minds had taken over. Days had passed since the bungee cords and he was finally able to move normally again. He would see Penny now only because he was deeply terrified of what would happen if they were alone in the laundry room tonight.

Sheldon pulled open the door to the restaurant. The hostess' smile died when she saw him.

"You're only supposed to be here on Tuesdays and you're never supposed to be here unescorted." She reminded him. Sheldon bristled at her words but his original intent took priority.

"I need to speak with Penny."

"She's on her break."

Sheldon pinched the bridge of his nose to summon patience. "Where might I find her?"

"Probably in the kitchen but…hey, you can't go back there!" Sheldon had already pushed through the swinging doors. Penny almost choked on the glass of water she was drinking when she saw Sheldon through the steam.

"What are you doing here?"

"I had to see you."
Penny took his arm and dragged him into the alley out back. Sheldon 's entire body recoiled in disgust. Thankfully, the dumpster was around the corner.

Their eyes met and held.

Penny's conscience gave her a kick. What had she done to him? Memories of Caltech flooded her brain. Now all she could think of was the structural integrity of his desk and his hands. All over her. A feather touch against her cheek brought her back.

"Don't." She pulled away.

Sheldon frowned and yanked her toward him, diving for her mouth. Penny's reaction was instant. She slapped him across the face. Sheldon was stunned. His hands drifted away from her shoulders and he stepped back. Penny's hand print blazed red on his cheek.

"Oh, god. Sheldon. I'm so sorry." Penny wrapped her arms around him but he remained rigid. Troubled by his unresponsiveness, she stood on her toes to press kiss after kiss along his neck murmuring apologies the whole time.

Penny melded herself to Sheldon, pushing him against the wall. She scraped her teeth along his earlobe and felt a spark of arousal in her when he grunted.

"Sheldon, " She whispered. "Show me you forgive me." Penny took his hands and brought them to her breasts. His hands remained still until one crept up and swiftly undid the buttons on her blouse.

He bowed his head and exposed the lace of her bra. Penny waited for him to free her breast. Instead, Sheldon's mouth covered her nipple over the bra. The effect caused Penny to claw at his shoulder. The friction of the lace, the wet insistence of his tongue, the cool air of the alley. She shuddered then bucked against him. Sheldon raised his head to latch more firmly to the curve at the top of her bra. He kept his other hand on Penny's ass not daring to explore further. Penny groaned as she pulled Sheldon's leg between her own and ground into it.. Sheldon's lips were anchored to the spot where her neck curved into her shoulder.

"Harder." She gasped and whimpered when she felt his teeth.

Penny's hand slipped down into Sheldon's pants. She licked her lips, wanting to take him into her mouth right here in this filthy alley. Instead, she stroked the full length of him. A noise came from the back of his throat; the hand on her backside slipped into her panties.

Penny loosened Sheldon's button to work him more fully. He threw his head back against the brick wall. Her hand moved faster-Sheldon's hips jerked.

"Penny," He gasped. She tightened her grip. "Penny, I want you to…"
"Yes."

"To stop." He opened his eyes and the shock of blue stayed her hand.

Silently, he removed her hand and refastened his pants. He pushed his sleeves down then reached up and chastely buttoned her blouse. Penny was still; the feel of Sheldon remained in her palm.

"I went most of my adult life without any interaction of this kind." Sheldon said softly. He wouldn't look at her. "You don't know how often I imagined being with you but it always felt different in my mind."

"Different?" She drew her brows together.

Sheldon finally faced her. "Yes , different. This…" He gestured to the alley. "is beneath us. I'm better than this. We both are."

Penny closed her eyes and turned away. How could she explain it to him. Would he understand the hold he had on her? As long as she kept this physical, combative, she wouldn't get hurt. Physical pain she could handle. The possibility that Sheldon would not or could not love her was beyond her ken. She opened her eyes to speak but his lanky figure was already walking out into the sunlight.