The girls were getting on Eleven's nerves again.

She had come to expect it during her eighth period algebra class at Hawkins Middle. It was the last class in her school day, and her least favorite, because it was the only one she did not share with her friends Mike, Lucas, Dustin, and Will. She instead sat at a table with three other girls - Lola, Bianca, and Nancy (Nancy confused El at first — she was quite surprised to learn that two unrelated people could sometimes have the same name).

They were giggling, as per the usual. El shut her eyes briefly and gave her head a little shake, trying to concentrate on what the teacher was saying. It had been nearly a year since Joyce had deemed her education caught-up enough to begin attending school, but she still struggled at times to understand all the new information.

And then she was immediately assigned a seat next to the three biggest gossips (as Dustin called them) in the school, because the old fashioned math teacher figured El would get along better with other girls. The logic was clearly flawed, as she found these particular three unbearable, but Eleven couldn't bring herself to really hate them — after all, they were nice and they meant well. But the presence of constantly giggling, whispering girls next to her did little to help her concentration…

"Psst, El!"

…particularly when they started talking to her.

"El, do you mind if we ask you a— a personal question?" That was Bianca. No sooner were the words out of the girl's mouth than she, along with Lola and Nancy, collapsed in a fit of giggles. El raised her head from her notes to stare at Bianca wordlessly, hoping she would get the message.

She didn't. "So, you and Mike Wheeler…" Bianca's voice dropped slightly as a mischievous grin spread across her face. She leaned forward and whispered, "Have you done it yet?" Her friends giggled harder. El wouldn't have thought that to be possible if she hadn't seen it. She wrinkled up her brow, confused.

"Done what?" She inquired blankly.

Lola and Bianca smothered full-on laughs, leaving Nancy to elaborate between sniggers. "You know — sex!"

This did nothing to clear El's confusion. She tilted her head at the unfamiliar word. "What is—"

"Table three! Enough side chatter, please!" came the teacher's crisp reprimand, and El fell silent abruptly. The girls quieted down, but not before Nancy patted El on the wrist, winking at her conspiratorially. Eleven was left to ponder the meaning of the word. "Sex". She couldn't figure out if she liked the sound of it. It was not a pretty word, she decided, though she supposed her opinion might change once she found out what it meant.

She had heard the word "sexy" before — one of the boys in her science class had said it to her when she first started at school and she had later asked Mike what it meant. He had turned bright red, like he did when he was embarrassed, and demanded to know where she heard it. When she told him, he had gotten angrier than she had ever seen him, storming to his feet and pacing around the Wheeler basement, muttering to himself.

"Mike? Why are you angry?" She had asked, worried that she had done something wrong. Mike turned to face her, his brow furrowed, and tried to explain, gesturing vaguely with his hands.

"He shouldn't have called you that. It means… like… attractive, you know? Pretty. But in a really disrespectful way. You don't— you shouldn't say stuff like that to a girl. To anyone. It's messed up." Eleven had remained silent, wondering why it was disrespectful to call someone pretty. After all, Mike had called her pretty not long after they had first met, hadn't he? She didn't feel disrespected then.

El now took her knowledge of "sexy" and tried to work out the strange new word. The girls had asked her if she had done sex with Mike. But that didn't make sense. How could you do pretty but disrespectful? Those were adjectives, she remembered from her English class. To do something, it had to be a verb. Could pretty be a verb? El didn't think so, but she wasn't sure.

I'll ask Mike later, she resolved. She was going to his house later, she remembered, along with Will, Dustin, and Lucas. The prospect brightened her up considerably, and El fidgeted with excitement until the end of the period, when the sound of the bell broke her from her thoughts. She quickly packed up her papers and folders and left the building.

Three hours later

"Seeya, Mike! Later El!" Dustin shouted. He exited, allowing the door to fall shut, but it opened again immediately. Will's head poked through the gap between the door and the wall.

"El, remember to call Mom when you're coming home, okay?" He waved and receded into the outdoors, followed by the slamming of the back door, and they were left alone in the Wheeler's basement. El, who had been sitting next to Mike on the small sofa, immediately snuggled closer and rested her head on his shoulder. He smiled at her and wrapped his arm around her, listening to her quiet breathing.

Mike gazed down at the small fifteen-year old girl nestled into his chest. She was beautiful, he thought, like he always did when he looked at her. He couldn't help it. Even when he first met her, dressed in a way-too-big yellow shirt, dripping with rainwater, shivering, pale and underfed, what little hair she had plastered to her skull… even then she was pretty. And now, at fifteen, hair still short but stylishly so (His sister Nancy called it a pixie cut, and liked to complain that she could never pull it off herself), matured in body and well-fed and dressed…

It almost hurt his heart, in the best of ways. He planted a kiss on the top of her head and she murmured quietly in response. Mike lay down on the sofa, staring at the ceiling, and Eleven crawled forward to lay atop him, her head on his chest, enjoying the way her body rose and fell with his breaths. For several long moments nobody spoke, before a thought seemed to cross El's mind.

"Mike?" She twisted and propped up her head so her chin was resting near his heart, gazing at him with dark brown eyes.

"Yes, El?"

"What is sex?"

The question was posed so innocently and so normally it took Mike entirely by surprise. His eyes shot open and he stared down at her.

"W-what!?" He could feel his face rapidly turning red and his heart beginning to race. How was he supposed to explain sex to El? And where had she heard it, anyway?

She frowned. "Some girls said it. In math. They asked if me and you did sex." She bit her lower lip and scrunched her brow, trying to remember their exact words. "But it makes no sense. You said sexy means pretty but bad, but how do you do pretty but bad?"

Mike was clamping his eyes shut and pressing his hands over his face. I should not be the one explaining this, he thought. Damn it, if only she had gone to school last year and had Sex Ed with all of us I wouldn't—

"Mike." She could tell the subject was making him uncomfortable. "You don't have to tell. I will ask Jonathan. Or Joyce or Hopper. Later." Eleven had moved in with the Byers after Will came back, and had grown to love them as family.

"NONONO!" Mike all but shouted, causing El to jump. He could think of not one thing worse than the idea of El asking Chief Hopper what sex was. He knew he would trace it back to Mike and oh God he carried a gun with him all the time… Eleven just stared up at him, bemused.

"Why no?" She had that way of tilting her head and asking those simple questions in that high, inquisitive voice that got to Mike like nothing else. He couldn't refuse her anything and he knew it. And right now he wanted to punch himself for it.

"Because… because…" Mike struggled to explain. "You know how I told you that kissing is a private thing? Like you don't talk about it with other people?" El nodded seriously. "Well, sex is like kissing, kind of, but… the next step. It's something you do with someone you really, really like. And you shouldn't talk about it with other people, especially adults."

El was frowning and biting her lip again, like she always did when something was confusing her. "Have we done sex?" She asked. Mike flushed again and shook his head vigorously.

"No! No, no. Trust me, you would know if we did, it's… much more extreme than kissing." Damn it, Wheeler, change the subject, change the subject… Talk about Eggos, Eggos will work, they always do. "El, are you hung—"

"But we kiss. All the time. And I really, really like you, and you really, really like me." Eleven didn't need to ask if that was true. She knew. "So why do we not sex?"

For the first time, Mike was uncomfortably aware of her hips pressing against his as she lay on top of him. He gently lifted her off of him and sat up to escape the compromising position. "El, it— it's not— only grown-ups have sex, El. It's not something for teenagers like us…" He stopped short because he knew that wasn't strictly true and he hated to lie to her. "Well, not for teenagers like — like us, us. You know? Like me and Lucas and Dustin." He glanced at Eleven to see if she understood, and knew immediately that she didn't.

"What about Nancy and Jonathan? Do they sex?" She asked after a pause. She knew they liked each other just like she and Mike did, plus they were older.

"Christ, El, I don't know—" He paused, feeling immediately guilty. His voice came out louder and sharper than he intended, driven by embarrassment, and he could tell by El's expression that she was hurt by his tone. He quickly apologized, taking her hand in his. "Sorry, you didn't do anything wrong. I shouldn't have yelled. But… I don't know, El, I really don't."

She looked at him and squeezed his hand. "Mike. Friends don't lie," she reminded him, bringing up an old expression. He sighed.

"Okay, yeah, they probably do. Have sex. That's, uh," he cleared his throat and flushed once more. "When Jonathan sleeps over here, that's probably what they're doing." Mike curled his lip in disgust and tried to get the image of his older sister's sexual activities out of his head.

He was dismayed to find that, rather than satisfying El's curiosity, his words seemed to only fascinate her further. "Really? They sex for the whole night?" Her eyes widened in awe.

Mike laughed despite himself. For being a super-powerful, monster-killing badass, Eleven's innocence never ceased to amuse him. "No, El, no. I… don't think it takes that long. But then they sleep together after. That's another thing people who like each other do."

El's eyes lit up as he said something she recognized. "Me and you have slept together!"

Mike nodded uncomfortably. "Uh, yeah, I guess we have." He studied the pattern of thread on the couch intently, avoiding her gaze. There was silence for a minute, and Mike was just beginning to relax when the girl at his side spoke up again.

"Mike?"

"Yeah?"

"What is sex like?"

Damn it, girl! "You know, El, I've never done it before, so I don't really know." He prayed that she was satisfied with his answer.

"How do you do it?" Innocent brown eyes blinked at him.

"Uhmmmm." Mike's voice seemed to have died on him.

"You said it's like kissing. But more, extreme?" She stumbled over the unfamiliar word, but quickly recovered. "Is it like this?" She leaned toward Mike, and before he could react, kissed him. Hard. Very hard, like she was trying to force her head through his. It hurt his lips and teeth, but he couldn't get annoyed. Not with her. He chuckled and embraced her and held her to his body lovingly.

"No, El, I don't think so. It's only like kissing because of who you do it with, you know? But it's different otherwise."

"Different how?" She inquired. Mike sighed, finally resigning himself to his fate. At least we can get it over with and change the subject.

"Well, for starters, I think, uh…" He winced. "You're naked when you do it."

"Naked? Why?" El was confused. Mike had told her, the very first day they met, that you weren't supposed to let people see you naked. Why was sex different?

"Aghhh, because… well, you have to do… something, and clothes kind of get in the way because it involves your body." Mike decided that maybe resigning himself to his fate was a bad idea after all. "And, El, I'm sorry, but I don't think I should be the one to explain all this to you. We'll figure out a way for you to learn. Maybe the nurse can give you a lesson or something one day after school. Okay?"

El studied his face. He was pleading her to say yes, she could tell. "Okay, Mike." He exhaled slowly and relaxed, and suddenly she realized how uncomfortable she had made him. She felt bad, so she kissed him again. He responded, pressing his lips to hers and wrapping his arms around her body. El moved eagerly into the kiss, suddenly poking her tongue into his mouth. She turned him and pushed him backward so they were lying down once more, her on top of him. His hands slowly made their way down her body toward her waist—

"Mike?" Came a call from upstairs. They leapt apart, both sitting straight upright.

"Yes, Mom?" Mike called back, exchanging a sheepish glance with Eleven.

"Is El staying for dinner, honey?"

He glanced at her inquiringly, and she nodded. "Joyce told me I could in the morning," she told him. He smiled happily.

"She is," He called to his mom.

"Can you two come up here and help me with dinner, please?" came the reply. The two teenagers stood, hand in hand, and began to head up the stairs. Before they got to the top, Mike suddenly stopped El and whispered urgently to her.

"El, please, whatever you do, don't say anything about sex up there. Okay?"

She smiled at him. "Okay."

A/N: So... just a funny idea I came up with one day. I love the Mileven pairing and was thinking about what would happen in their relationship as they matured. Inevitably, the topic of sex would be introduced at some point in their teenage lives - I like to think this is how it would happen. Fifteen might be a bit old for hearing about sex for the first time, but hey, any younger and it's verging on creepy, right? Hope you enjoyed, anyway! Would sincerely appreciate any reviews.

Over and out!