Penny woke face down on her bed, a small puddle of rapidly cooling drool forming under her cheek. Feeling suddenly grossed out, she lifted her head only to let out a cry at the pain that shot through her brain as she moved.

Oh, god.

Squeezing her eyes shut to block out the horrifying sunlight, she took a mental inventory.

Bed empty? Check.

Apartment empty? Check.

Clothes on? Check.

Appropriate clothes on? Um...nope. She was still wearing the hundred dollar humiliation dress. Clearly the zip had proven too worthy an adversary at 2am.

So far though, not too bad. But there was something else clamouring for her attention... something about a guy. She had the feeling she usually got the morning after a good date; that buzz of excitement, the anticipation of where it was going to lead.

Which was confusing, because she was pretty sure her date with Rick had ended with her calling him a bastard in front of all his friends before storming out and hitting the bottle in a one-woman pity-party. Which, whilst giving her a certain amount of satisfaction, had not led to the particular kind of satisfaction that she usually associated with the grin that was itching to plaster itself over her face.

She decided to stop worrying about it until she had persuaded her brain to stop bouncing off the walls of her skull, and very gently sat up. By the side of her bed were a huge glass of water and a packet of pain pills, which seemed like excellent planning on her part. Maybe she hadn't been that drunk? She downed the pills and drained the water, then started feeling around for the zip on her dress. Thirty frustrating seconds later she gave up, reached for the bottom of the dress and hauled it over her head. She heard the fabric tear and winced. No refunds on that, then.

Right, shower, then coffee.

She was sure the guys wouldn't mind her borrowing some milk.

....

Sheldon had slept badly. After Penny had left he had tried to go back to sleep, but his head had been spinning. Two cups of hot milk later and he was starting to wish he had some of Mrs Wolowitz's pills.

He wasn't sure what was bothering him most about the encounter. Whilst he was not, contrary to popular belief, a robot, he certainly didn't have the same level of libido as Leonard et al appeared to. Their obsession with women appeared to him to border on the pathological at times. And yet, he had kissed Penny. Twice. More, he had issued her an invitation; to return when sober, presumably with the intention of taking things further. Why had he done that? He had meant the things he had said to her; Sheldon Cooper did not do meaningless platitudes. But to go from appreciating someone's attractive qualities to issuing an invite to have sex? Sheldon Cooper didn't do that either. Usually.

Her unexpected kiss had clearly awakened something in him; some desire that he had neglected in favour of physics. He wondered if it was specific to Penny, or if a kiss from any woman would have had that effect on him. It was this thought above all that was causing his sleepless night; or rather, its implications.

At 6am he abandoned his bed and got up to prepare for work. He pondered asking Leonard for advice when he returned, but the thought of sharing what had happened made him feel uncomfortable. He felt intuitively that this should remain private; and besides, Leonard was sure to voice some kind of ridiculous territorial claim over mating rights for Penny.

The thought made him furrow his brow.

He clearly needed to do more research.

....

Penny soon ascertained that her milk was, as she had expected, lumpy. She grabbed her key to the guys apartment; Sheldon would bitch, but she didn't care. As she thought about him, something nameless niggled at her; nothing she could put her finger on, but a definite...niggling.

Maybe she needed to cut down on the drink. It was doing weird things to her.

As it turned out, she needn't have bothered with the key; Leonard was coming up the stairs as she opened her door, looking rough after driving all night to get home. They looked at each other.

"Wow, you look awful."

"Jeez, what happened to you last night?"

They both smiled ruefully. Leonard spotted the mug in her hand. "Coffee?"

She shook her head. "I have that. Just stealing milk today."

He grinned. "Come on in. I'm driving Sheldon to work so you can steal in peace pretty soon."

There, again, was that niggle. She frowned briefly, then shook herself as Leonard opened their door.

"Sheldon! I'm back. Come on, lets go before I fall asleep and you have to dig out the bungee cord again!"

Penny wandered over to their fridge and pulled it open, perusing the contents. She heard the bathroom door shut.

"Leonard, could you please not shout? I had very little sleep last night and now have a headache." He sounds tired, she thought, which was quickly followed by well of course he's tired, you woke him up. Which didn't make much sense. Confused, she swung the door of the fridge shut.

Which revealed Sheldon, looking at her with the expression of a deer caught in headlights.

Pretty much the same expression he had when you tried to seduce him last night, actually the anonymous thought-voice chimed in.

Holy crap on a cracker.

The two stood, face to face; Penny's jaw practically on the floor and Sheldon trying admirably to recover himself. He had somehow expected to have a little more time to plan for this situation, but never mind. He drew himself up.

"Good morning, Penny. Stealing our milk again I see." He raised one eyebrow, Spock-like.

Penny managed to close her mouth and threw a quick glance at Leonard to see if he'd noticed anything. He was sat on the arm of the couch looking like he was about to start snoring, so she figured they were fine.

"Damn. You caught me, Sheldon." She tried to read his face but it was inscrutable. For a long moment they just continued looking at each other, before a grunt from Leonard pulled them back. He had slipped off the couch. Sheldon suddenly turned to him. "Leonard. Why don't you wait in the car? The fresh air may make you more alert and so less likely to kill us both in a burning fireball on the way to work." Leonard nodded dully.

Sheldon waited until he'd left, then turned back to Penny.

"How is your head this morning? Did you follow my advice?"

Despite her shock, Penny smothered a small smile. After everything that had gone on last night, Sheldon was worried about her hangover. It was kinda sweet.

"It's fine Sheldon. Thank you. Um. How are you?" She was worried he would be freaked out, but if he was then he was hiding it well. He appeared to give her question some thought.

"I will admit to a certain...confusion. Also, I was unable to return to sleep after your visit so am suffering the effects of mild sleep deprivation. However, I do not appear to have any negative feelings regarding what occurred." She looked at him, before asking the big question that was on her mind.

"Ok. So how do you feel about what didn't occur?"

He looked at her blankly. "I don't understand."

She sighed. She could feel her headache coming back.

"Sheldon...did you mean what you said? Just before I left? About...next time?"

"Oh." He looked surprised. And confused. "I'm not really sure. Certainly it was very enjoyable, but I have very little experience in this area. Possibly I hadn't thought through the consequences of the...invitation."

"Oh." It was Penny's turn to be surprised, although she didn't know why; had she really expected him to still want her in the cold light of day? This was Sheldon, a man to whom sex was like the surface of the moon; something vaguely interesting from a scientific point of view, but not somewhere he was particularly interested in visiting. She was also surprised to realise that surprise wasn't the only emotion there. Something approaching disappointment appeared to be lurking in the background, and she filed it away for further consideration after coffee. "Ok. I guess we should just forget it happened then, right?"

"That sounds...sensible" Sheldon agreed, although she thought she saw a small frown skip across his face as he spoke.

"You should probably go. Leonard'll be asleep by now and I'm probably still too far over the limit to take you myself." She gave him a small smile, and watched as he nodded and picked up his messenger bag. He reached the door, then turned, fiddling with the strap across his chest.

"The remainder of what I said to you last night is still applicable, Penny." She blushed a little, remembering his words; they were the nicest things anyone had said to her in a long time. And he had certainly seemed to want her then. She found herself idly wishing he didn't have so many damn morals.

"And, Penny?"

She met his eyes from across the room. "Yes, Sheldon?"

He paused, considering his words carefully. She realised she was holding her breath.

He frowned slightly, then reached for the doorhandle.

"Please don't take all the milk."

He was gone through the door before she had found something to throw at him.