Amy's birthday is approaching, and I wanted to do a little something to celebrate. This ended up being a little silly. I hope you enjoy.

Amy lay awake staring at the ceiling on the eve of her birthday. She was too excited to sleep, thinking of her annual gift. She twisted her head to the left and peered at her fiancé in their nearly-dark bedroom. He lay on his side facing away from her, so she watched the rest of his body for signs of alertness.

Squinting at him without her glasses on didn't work, so she gently placed her hand on his ribcage. It rose and fell slowly and steadily. She would probably have to wait until morning. Luckily, her birthday fell on Sunday this year, so they could take all the time they needed making love. What time was it anyway? She carefully rolled over and pawed at her nightstand. Where was her phone?

She peered over her shoulder to be sure she hadn't woken Sheldon. She was both relieved and disappointed that he still appeared fast asleep. Sighing, she methodically combed the nightstand surface with her fingers. They made contact with her glasses, lotion bottle, Kleenex box, lamp, and the MRI of Sheldon's brain, one of her most prized possessions. Everything was there except her phone. Had she left it on the coffee table? No matter. It wasn't that important anyway. She lay back against her pillow and closed her eyes.

Amy awoke to the sound of her name. She blinked and saw Sheldon hovering over her. "What time is it?" She croaked.

"Just after midnight. Happy Birthday," he murmured in a low, sexy voice.

She sat up against the headband and rubbed her eyes. "Really? It feels more like 3 a.m."

He consulted his watch then showed it to her. "No, it's 12:03, and I know it's right because my watch is..."

"...linked to the atomic clock in Boulder, Colorado. It's accurate to one tenth of a second," she finished for him. "I know. I don't doubt you. It's just that it felt like a long time for me to fall asleep. It's hard to believe it's only two hours since bedtime."

"Now that we're both awake, shall we begin with your birthday festivities?"

"Yes! I'm always eager for your gifts."

He reached under the bed and extracted a gift bag with 'Happy Birthday' emblazoned on it in multicolors, surrounded by balloons. He watched as she pulled the red tissue paper from the bag and set it on her nightstand. Amy dug her hand to the bottom of the bag and removed the contents.

She stared at the object and frowned. "My phone? I don't understand."

"I added some reminders to your calendar. Open it to January 17."

She obliged, furrowing her brow. "8 p.m. S+A. What does that mean?"

"S+A stands for Sheldon and Amy," he explained.

"I kind of figured that, but what exactly happens on January 17?"

He gently peeled her fingers off her phone and set it aside. Taking her hands in his, he gazed into her eyes. "Amy, my gift to you is more frequent sex. Once a year isn't nearly enough, so I scheduled sessions on the 17th of every month at 8 p.m."

"Oh, Sheldon!" She threw her arms around him and squeezed.

"And that's not all. I also scheduled Valentines Day, my birthday, and our anniversary. Plus, I would be open to occasionally sneaking in some extra sessions."

She kissed him hard. "Thank you!"

"I'm so glad you like it. Now prepare yourself for our first session." He flipped her onto her back, hovering over her in his red plaid pajamas.

xxx

One month later, Amy and Sheldon sat on their neighbors' couch, consulting their watches.

"That's like the tenth time you've checked your watches. Are we boring you?" Leonard asked.

"No, I'm sorry. It's just that we need to..." Amy caught her fiancé's stern look, "leave in a few minutes," Amy finished lamely.

Penny eyed her friends curiously. "What's so important on a Wednesday night?"

"That is none of your business," Sheldon huffed. "Come along, Amy. It's almost time anyway."

"Sorry," Amy called over her shoulder as Sheldon led her out the door, across the hall.

Penny shut the door behind them. "What was that about?"

Leonard shrugged. "Better not question it. You know how weird Sheldon is. Let's forget about them and enjoy the quiet."

Penny sat down and patted the spot next to her on the couch. "I know how we can enjoy the rest of our evening." She winked at her husband.

Leonard took the proffered seat. He brushed back a lock of his wife's hair then froze. "What was that?" They cocked their ears toward the door.

Penny wrinkled her nose. "It sounds like an animal in distress." She stepped into the hall and frowned. "I think it's coming from Sheldon and Amy's apartment. I hope they're not doing some weird experiments with animals. That could explain their odd behavior." She creeped up to the door and rested her ear on it.

"Penny, that's eavesdropping. We need to give them their privacy. They could just be watching Animal Planet."

"Shh... I hear another sound, but it's too faint to make out."

Leonard sighed and joined her. He pressed his ear to the door and concentrated. "That's just Amy giggling. Can we go now?"

"That doesn't explain the other sounds. I'm going in."

"We can't just go in there," Leonard reasoned, but it was too late. Penny was already pounding on the door.

"Who is it?" Amy's muffled voice inquired.

"It's me and Leonard. Can we come in?"

"That's not a good idea. We'll see you tomorrow," the neuroscientist replied.

"What are you doing? We heard some strange sounds. Is everything okay?"

"We're fine!" Sheldon shouted. "Go away."

Before Leonard could stop his wife, she ran to their apartment, retrieved the key to 4B, inserted it in the lock, and turned. "Penny!" he hissed, as she quietly entered the apartment.

She surveyed the living room and kitchen. Nothing out of the ordinary. Her eyes traveled to the closed bedroom door. Moans emanated from the room punctuated by Sheldon muttering 'vixen'. "Oh, God," she groaned softly. She quietly slipped out the door then ran to her apartment and slammed the door.

"Penny, what happened? Were they actually experimenting on animals?"

She shook her head in the negative. "They were having sex. Oh, God. I'm a terrible friend."

He joined her on the couch. "You're not terrible, just concerned."

"How could I think my best friend was doing unspeakable things to a living being?" She wailed.

"Well, she kind of is."

She glared at him. "Not funny, Leonard."

"Let's forget about them. Why don't we watch one of your reality shows to take your mind off it?"

Penny relaxed as they sat back and watched The Real Housewives of New Jersey. Leonard had been extra sweet, preparing snacks and wine. He pulled a blanket over their laps, and she rested her head on his shoulder. The on-screen action was the perfect distraction, and soon the incident was all but forgotten.

"This is really nice. We should do this more often..."

They jumped as a blood curdling scream pierced the relative quiet.

"Amy! Someone broke in! Oh, dear Lord!" Sheldon shrieked.

"Uh oh," Penny murmured. "I didn't shut their door." She crept over to the door and peered out the peephole. The door was flung open, and Sheldon stood by the couch in his bathrobe scanning the room.

"My laptop and Xbox are still here," he sighed in relief.

"My laptop is here too. Perhaps it wasn't robbers. It's possible in our rush to get home, we didn't close the door properly."

"I know we did. I heard the click when you turned the deadbolt."

"I'll check for signs of a break-in." Amy tied her robe tighter and stepped into the hall. Her eyes we're drawn to a key in the lock. She poked her head in the door and noted their keys in the bowl, as they should be. She plucked the key from the lock and closed the door behind her, dangling it in front of her fiancé.

"What's that?"

"Our spare key."

"Leonard and Penny!" He grumbled. "Wait, that means they came in after we told them to leave. They heard us! Oh, dear Lord! This is unacceptable! I'm going over there to confront them."

Amy grabbed his wrist. "Sheldon, wait! It's late. Let's confront them in the morning."

"No. They violated our privacy, so I don't care how late it is." He marched across the hall, performing his triple knock much louder than normal and waited.

"Sheldon, they're probably sleeping. Let's go to bed and worry about this in the morning," she begged.

He ignored her request. "Hand me the spare key. I'm going in."

"Sheldon, two wrongs don't make a right."

"Hand me the key, please."

She sighed and placed the key in his palm. Penny slid the chain lock in place and backed away from the door. The deadbolt clicked. Sheldon pushed the door open but was met with the resistance of the chain.

"What the hell, Sheldon!" Penny yelled.

"You invaded our home, so I planned to do the same to yours."

Amy joined her fiancé, peeking through the small opening. "I apologize for Sheldon's behavior, but to be fair, he was only doing it because you entered our home uninvited. All I want to know is why."

Penny unlocked the door and faced her neighbors. "I'm sorry, Ames. We heard some strange sounds coming from your apartment and were concerned, especially since you left our place so mysteriously."

Sheldon and Amy exchanged an embarrassed look. Amy twisted her engagement ring around her finger. "You've probably already figured out what we were doing."

Leonard reddened. "It's Penny's fault."

"Hey!" She glared at her husband. "Thanks for throwing me under the bus."

"It doesn't matter who's to blame. Can we just forget this happened? It was an honest mistake. Sheldon and I will try to keep the noise level down next time."

"For future reference, please do not disturb us after 8 p.m. on the 17th of each month, Valentine's Day..."

Leonard cleared his throat. "How about if we just agree not to use our spare keys unless there's an actual emergency or if we're apartment sitting."

"Deal!" The girls agreed.

Amy gave Sheldon a look. "Deal," he grumbled.

The friends shook on it then returned to their respective homes.

"Who knew my gift to you would cause such a ruckus," Sheldon muttered, as they disrobed and slipped under the covers.

"At least they can't tease us about our sex life anymore."

"You know, the schedule doesn't specify how many times we can engage in love making per date. It's still January 17th."

"I like how you think, Dr. Cooper," she purred. "Do you think you can keep the noise to a minimum?"

"I downloaded an app that can alert you if the decibel level gets above what you set it to. I've used it in my office to prove my point to President Siebert when he didn't believe how loud the geology lab gets when they run their confounded sieve shakers. Perhaps we can use it to experiment here."

"You're sexy when you talk science," she growled. "Perhaps we'll need to increase the frequency of our sessions until we get the desired effect."

He set up the app then scooted closer to her. "I agree. We'll need sufficient data."

She kissed him hard, their lips making a loud pop when they separated. Sheldon's phone beeped, and they both dissolved into a fit of giggles. "I think we can agree that we need to increase the decibel level it can handle."

"Agreed." He increased the setting then turned to her. "You know, for this experiment to work properly, we'll need to test the highest decibel level we can get away with before Leonard and Penny can hear us. I suggest starting on the high end."

"Sheldon!"

"What? It's only logical."

"But we promised..."

"We said we'd keep the noise level down. We didn't specify how much."

Before she could respond, he flipped her onto her back, covering her naked body with kisses.