I don't own the Big Bang Theory, or it's characters. I do have a pretty sweet collection of stuffed monkeys. Just so you know.
Sheldon was distracted. He was working on a problem and walked in without thinking. His mind was on the driving arrangements for next month's Comic-con. He looked around vaguely without seeing her, so he wandered over to her bedroom. His world spun out of control. He told himself to close his eyes. He told himself to leave. He told himself to breath.
Penny was standing in front of her closet, completely nude. She was flipping through the hangers, searching for something. She grabbed a sundress and threw it across the bed, then she walked to the dresser, She pulled out knee socks and slipped them on slowly. She stepped into a tiny black thong and slid it up her creamy legs. Sheldon slowly backed up trying not to alert her to his presence. He quietly made his way out of her apartment. Once in the hall he sprinted for his room. He shut the door behind him and flopped down on his bed. He tried to calm his breathing.
After a few moments his hand slipped down and released his aching erection. His hand moved slowly as his mind's eye roamed over the image of her naked body. Sheldon moaned softly as he remembered the feel of her breast in his hand the night she hurt her shoulder.
"Penny," he softly gasped.
He squawked in alarm and scrambled to cover himself. He looked at Penny lounging against his door. She reached out and locked it before moving toward him. She untied her robe and let if fall to the floor. She was only wearing the knee socks and thong.
Sheldon watched her move closer and closer. His body trembled as she stopped right in front of him. He looked up at her with a mixture of hunger and panic. She smiled reassuringly at him and took his hands in hers.
"I just showered," she said. She moved his hands to her hips and placed her hands on his shoulders. "Why did you run away?"
Sheldon licked his suddenly dry lips. Could he do this? Tentatively he moved one hand up her waist and stopped just under her breast. Penny moaned softly. Sheldon's confidence grew with that sound. He moved his hand higher and cupped her breast. His other hand dug into her hip tightly.
Penny moved between his legs and slowly dropped to her knees. Sheldon's eyes widened as her hands slid down his chest. Penny leaned in and pressed little kisses along his jaw. Sheldon groaned and turned his head to press his lips to hers. He threaded his fingers in her hair and pulled her closer.
Penny pushed him back onto the bed and straddled his hips. They both gasped as his erection brushed against her core. Sheldon looked at the desire in her eyes and felt a rush of power. Penny wanted him!
"Please, Sheldon," she begged. "Touch me."
Sheldon slid his hands through her hair and down her back. He reached her hips and pressed her against him. Penny wiggled against him and all his reservations dropped away. He reached down and shoved her thong out of the way. Sheldon looked up at her questioningly. Penny shifted her hips until the head of his penis was poised at her entrance.
"Please Sheldon," she whispered. "I've wanted you for so long."
He surged upward immediately, burying himself inside her. They both shuddered, reveling in the pleasure. Slowly he flexed his hips and Penny began to move. They matched each other thrust for thrust.
Their lips met again and they lost themselves in each other. When Penny's orgasm hit, it pushed Sheldon over the edge. Penny collapsed beside him and they both tried to catch their breath. Sheldon marveled at how peaceful he felt.
"Penny," he said quietly.
"Does this mean we are friends with benefits?" he asked hesitantly.
Penny stroked his forearm. "Is that what you want?"
Sheldon looked over at her, too shy to make the first declaration. "What do you want?"
Penny kissed his cheek softly. "I want you, Sheldon, however you let me. Whatever makes you most comfortable. I won't push you into something you don't want, or aren't comfortable with. But I do want you. I have for a very long time."
Sheldon's eyes widened at her admission. He licked his lips nervously. "What if I said I wanted to be your boyfriend?"
Penny nodded happily. "I'd like that. A lot."
Sheldon blushed slightly. "What if I said you had to marry me?" he teased.
Penny beamed at him. "Okay. But you can't say your vows in Klingon."
Sheldon looked at her in shock. "Really?"
Penny rolled her eyes and snuggled closer. "Fine. You can speak Klingon, but I'm doing mine in English."
Sheldon looked at her in astonishment. After a moment he grinned. "You do realize you just made a verbal, legally binding, agreement to marry me, right?"
Penny kissed him tenderly. "Yep." She laid her head on his shoulder and yawned.
Sheldon reached out and pulled the blanket over them. "We can tell everyone in the morning," he said cautiously, sure there was a bazinga in there somewhere.
"Okay, sweetie," Penny said. "Can I stay the night?"
Sheldon wrapped his arm around her shoulders and nodded in amazement. He watched Penny drift off to sleep with a great deal of satisfaction. He wondered why his friends had so much trouble with relationships. He had not only established a relationship, but had already made it permanent. As he drifted off beside her he wondered if she would agree to a Comic-con wedding.