A/N: I really shouldn't have done this. I have other things I'm doing that need done. But dammit if I can't resist a wall sex prompt! Written for calderonecheesecake over on Tumblr. I hope you like it!

Sheldon had told everyone that this week no one was to disturb him except Penny. Partly because of their relationship status, but mostly because she wouldn't have listened even if he had.

So that Thursday (and not even an Anything Can Happen Thursday, just a regular one) they cuddled on the couch (per her demand) and watched the new Star Trek movie (per his).

Sheldon planned on going to sleep right after, but Penny had other plans. A hand on his thigh and a kiss to his neck clued him in.

"Penny," he gasped. "You know I work tomorrow. I need my REM sleep." It was a pathetic attempt and he knew it.

She rose up on her knees and whispered in his ear, "I also know you sleep better after sex."

With a groan Sheldon's eyes fluttered closed and he surrendered. Penny straddled him and bit his bottom lip. He bucked his hips and the friction sent a jolt through his system. His hands went to her hips and clenched hard. It was a long, slow, purposeful kiss, meant to ignite the spark.

Her hands slid up his ribs and removed his shirts while he did the same to her. Next came her bra. It was a point of pride that he could undo it with one hand the first time everytime.

Her shorts and panties pooled at her bare feet when they stood. He removed his shoes as they walked, still fighting for dominace. He ducked down and kissed her stomach as he removed his socks, dipping his tongue into her navel. She ran her hands through his short hair, and when he got up to her nipple she scratched his scalp.

Up the step into the hallway and his pants dropped. Penny slid down his underwear and kissed the underside of his erection. It twitched and touched her nose; she smiled and licked it. Sheldon groaned again and threw his head back. He pulled her back up and latched onto her neck, careful not to leave a mark.

Well, much of one, at any rate.

Penny's fingers raked down his chest not so carefully, but Sheldon wasn't complaining. She threw a leg over his hip to pull him closer and he shoved her against the wall. He liked control in all aspects of his life and she was happy to surrender in this one.

One hand held her arms above her head and the other lifter her leg above his hip again and he entered her, swiftly and smoothly. As with all areas, once he was introduced to the subject he quickly became an expert on pleasing Penny.

Slow to start, he slid in and out in long strokes, squeezing an ass cheek and gripping her hand. Each stroke was slow, but forceful, hitting the right spot every time. The only sounds were her whimpers, his heavy breathing, and the sound of flesh hitting flesh hitting the wall.

Sheldon let out a grunt and Penny knew he was close. She freed her hands, gripped his shoulder for leverage, and touched herself with the other. The added stimulus quickly sent her over the edge; the quivering of her orgasm sent him. He bit down on her shoulder to stifle his cry, but she had no such inhibition and yelled his name along with a deity neither of them believed in.

Penny's legs gave out and she slid to the floor. Sheldon followed, comfortable with knowing exactly how clean his apartment was.

"Oh, I don't know about you, but I feel better." Penny leaned her head on Sheldon's shoulder and closed her eyes.

"Yeah," he exhaled. "We should adjourn to the bedroom. The floor is not conducive to comfortable REM sleep." He looked at the trail of clothes and twitched. "We should also clean up after ourselves."

Penny squeezed his thigh and said, "We can do all that tomorrow. Now it's sleepy time." She pushed off the floor and got up, then pulled him up, too. "Come on, Shelly. Cuddle me, shipmate."

The nickname annoyed him, but the Doctor Who reference made him smile. "Yes, Penny."