Anna wasn't the best driver, even on a good day; and today, was not a good day.

She'd skipped afternoon classes – having got Rapunzel and Flynn to cover for her – and had driven straight home. She heard the smash when she pulled into the driveway, and when she got out of the car - and looked to the front of the vehicle, she saw the broken flowerpot. "Mom is going to be pissed." She winced, and shook her head. This really wasn't a problem for her right now.

She barged in through the front door, and ran upstairs – stopping right outside her sister's bedroom – and knocked.

"Go away, Anna. You should be in school." Elsa's voice came from behind the closed door.

She frowned and ground her teeth together. "I'd be there if you had actually answered your phone, or replied to one of my hundred text messages!"

"I don't want to talk."

"Well, I do!" She put her hand on the doorknob and jiggled it.

Locked.

Of course it was.

It was just typical of her sister to just shut herself away and hope that the problem would just somehow miraculously disappear. Well, she wasn't going to let that happen. "Open the damn door!"

"No!"

Anna growled in frustration, and sat on the floor, with her back against the door. "Elsa," She spoke her sister's name softly. "I know you're freaking out, but what good is locking yourself away going to do?"

There was no reply.

She let her head fall back against the wood, and sighed.

This was her fault. She had screwed up her relationship with her sister – just because she'd been cold.

"Elsa." Anna nudged her sister's sleeping form.

"Wha?" Her sister turned over and looked up at her with half closed eyelids.

"The heating's stopped working again. Can I sleep with you?"

Elsa groaned, but threw her covers back anyway; Anna jumped in and landed on top of the blonde. "Hi." She grinned down at her sister's face, and she adjusted herself so that she could be a tad more comfortable, and that resulted in her essentially straddling Elsa's leg.

"This is really inefficient." Elsa croaked out, and then cleared her throat. "Why do you need to be on top of me?"

"Why wouldn't I? That's the real question here." Anna smiled, and rested her head on her sister's shoulder; tucking herself in the crook of Elsa's neck.

"Urgh." Her sister huffed, and awkwardly pulled the blankets back over the two of them. "I hate you sometimes. You make my life so much more complicated than it needs to be."

"No you don't hate me." Anna sulked. "Take that back!"

"Fine. I take it back."

She kissed Elsa's neck; and it tasted of vanilla. "Thank you."

"Mmm hmm." Elsa responded; putting her hands around Anna's back, and began trailing her fingers up the redhead's spine.

Anna smiled. Her sister knew her all too well – This had always been the sure fire way of getting her to go to sleep - But it had been quite a few years since she'd needed the help though; her chronic insomnia that plagued most of her childhood, seemed to disappear when she hit puberty. But she did miss having Elsa tickle her back though – even if she never told her so.

"Are you in the office tomorrow?" She mumbled.

"No. Dad gave me the day off."

"Generous of him." Anna said distractedly; and she moved her hands from her side, and slipped them under Elsa's nightshirt; and started brushing her thumbs over her sister's ribcage.

The blonde was surprised by the contact, and her body jerked in response; her knee lifting slightly. "Anna, your hands are freezing." She chuckled.

"Yeah." The redhead responded and stared at the snow white neck with wide eyes. Her sister's sudden movement caused the blonde's leg to brush up against Anna's centre - and apparently - her body liked this.

Her brain on the other hand – was confused. She'd felt something similar to this when she and Hans were fooling around, but nothing quite so… Intense… as it had just been.

Did she just get turned on by her own sister?

"Anna? Are you alright?"

"Yes. Why?" Her voice trembled slightly. She wanted to move from her position.

But at the same time – She really didn't.

"You're breathing really hard; like you're out of breath."

"Oh." She replied dumbly and she inhaled deeply, then slowly released her breath out over her sister's neck. Elsa pressed her fingers into her back, and Anna heard a noise come from the back of her sister's throat.

Oh God!

Whatever that noise had been - it made her libido feel like it was crackling with electricity; Her brain had decided it wanted nothing more to do with this weirdness - and that left only her libido in charge.

She pushed her hips into Elsa; she wanted that contact again. Her sister moaned and her heart started to pound.

FuckFuckFuckFuckFuck. I should not be doing this. I should not be feeling this – This moment of clarity only lasted long enough for her to ignore it, and then shifted her hands from Elsa's ribcage, further up.

This time, it was the blonde that jutted her hips up – And she lifted the leg that wasn't being straddled by Anna, and hooked it around the redhead's ankle; then slowly pulled it out, so that the younger sister's legs were being parted.

Anna removed one of her hands from under Elsa's shirt, and grabbed at her sister's thigh; her whole body pressed forward – and the hand still on her sister's torso slid up to just beneath her breast – and pushed under the bra – just enough to feel the soft flesh on her fingertips. Elsa's body bucked into Anna, and this encouraged the younger sibling to keep her movement going. She rocked her hips in a steady motion – the heat between her legs growing with every thrust, and she moved her face closer to Elsa's neck.

She pressed her tongue against the warm skin and drew tiny, wet circles on it. Her sister buried her hand in her messy hair - while the other hand scratched at her back through her tank top.

Anna groaned, and she increased the pace her of her hips, and dragged her teeth over the smooth neck. She bit down gently and then sucked.

Elsa gripped a handful of her hair, and started writhing underneath her – The moans that the blonde elicited took control of Anna's libido, and she increased the friction between them.

It felt mindless now.

Nothing but the sound of pleasured moans - and the need to hear her sister fall apart beneath her.

When it happened, Elsa shuddered and pulled Anna as close as she could, and the redhead could feel her heartbeat against her fingertips.

Their breathing became less frantic, and finally evened out.

There were a few moments of silence, and then the blonde pushed her sister off her. "You need to go." She said. "Now."

Anna's throat tightened, and she left as quickly as she could – when she was fully in her own room – she began to sob.

"Elsa?" She knocked on the door again, and shifted her position on the floor because her foot had gone numb. "Please. I'm sorry!"

Silence.

"We don't have to talk about it. We can never talk about it ever, if that's what you want! But please don't shut me out. We'll pretend that it never happened, and I can get my sister back."

There was still no reply; but she heard the sound of her sister sitting by the door.

At least that was something.

She turned her head so that her lips were as close to the wood as they could be without touching it. "You're my best friend." She whispered – knowing Elsa would hear her. "And I fucked it up. Just tell me how I can fix it."

"I don't think it can be fixed." Elsa replied.

Her heart sank. "So that's it? We can't have anything? We'll just be two people who happen to live in the same house?"

"It's probably for the best. I'll be going to college soon, so it'll be less awkward after that."

"You're being so fucking logical!" She banged at the door as tears began to well up.

"And you're being childish." Elsa said gruffly, and Anna heard her sister getting up.

"Okay! I'm sorry." She said trying to keep her sister nearby. Yes there was a door between them, but she didn't want to lose closeness. "If you really think we should just ignore each other from now on - Then let me in one last time."

"I don't think that's a good idea."

"You owe me this!" She snapped and stood up. "Don't make me get Dad's tools; I can break the lock, and you know I will."

"Fine!"

The sound of the door being unlocked made her feel nervous; and when she saw Elsa she thought she was going to throw up.

Her sister looked perfect all of the time, but right now she looked like shit; her eyes were red and puffy, and there were blotches all over her porcelain skin.

She hesitated before she stepped over the threshold. She'd really, really fucked things up. "Thanks." She said quietly and went to sit at the end Elsa's bed.

"What is this going to accomplish?" The blonde asked sadly, as she closed the door.

Anna shrugged; and watched her sister take a seat at her computer desk.

"Great." Elsa said sardonically.

"I don't want to lose you!"

"I think we've both lost each other at this point, don't you?"

"No! Why do you say that?"

"Anna! We're sisters! Sisters don't make each other…"

"Orgasm." The redhead finished.

Elsa's jaw clenched tightly. "I know we've always been close, Anna, but what happened last night was too fucking far!"

"I said I was sorry!" Anna whined.

"Stop saying sorry!" The blonde stood up and began pacing.

"I don't know what else to do! I don't know how to fix what I've done."

"This wasn't entirely your fault; and that's the fucking problem!"

"What do you mean?" She asked and got up; getting in her sister's path when she didn't receive an answer. "What do you mean?" She repeated.

Elsa stared at her for a long time; not saying anything – and then she rubbed her hands over her face and shook her head. "I wanted you." She said finally, and collapsed onto the chair behind her.

Anna mouth twitched into a smile as stepped closer, and then straddled the blonde's lap; the short skirt she wore riding up her thighs. "And now you don't?" She asked wrapping her arms around Elsa's neck.

Her sister didn't answer – she just placed her hands on Anna's exposed legs, and ran her fingers upward; making the redhead shiver with anticipation.

She hadn't expected this - She wanted it – But she hadn't expected it.

She'd spent every waking minute since last night - thinking about Elsa moaning underneath her. She'd gone through every conceivable emotion before she finally accepted that she wanted her sister. But after how Elsa had acted afterwards – she didn't think it would ever happen again; and she just couldn't live without her. So she decided - after spending the whole morning in school thinking about how she was going to make it up to her – she would say sorry, and keep her feelings to herself.

She gasped when she felt fingers brush at her core through her panties; and she grabbed a handful of platinum blonde hair – yanking it so that they were face to face. "I want you inside me." She whispered, and nipped at her sister's bottom lip.

"Fuck." Elsa groaned.

Anna's skin felt cool as her sister pushed aside her underwear, and she shuddered as a finger brushed against her entrance, but she kept eye contact with the blonde.

One finger slid inside her slowly, and then was pulled out at the same pace; rubbing her juices over her clit. "You're so wet." Elsa said in complete awe.

"You'd better do something about that." She growled; Libido was rearing its head again – and it was too horny to be teased.

Elsa gave her a small nod; and when she entered the redhead again - she pushed two fingers inside, and her thumb covered her sister's small bundle of nerves.

Anna pushed against the digits inside her; grinding herself harder as she brought her lips to her sister's. Their kisses were messy, and primal, and interrupted with moans from them both. She let one her hands that were buried in her sister's hair drop to the waistband of Elsa's pyjamas, and she slid her hand beneath the elastic, and brushed along her sister's clit.

The position was awkward. Their wrists kept bumping into each other, but she needed to touch Elsa; needed her to feel what she was feeling.

Their thrusts increased with every passing moment; and she pulled away from her sister's mouth. "Harder. Faster. Deeper." She demanded breathlessly.

Elsa's eyes narrowed - and she smirked as she removed Anna's hand from her pyjamas and lifted her up – still inside her - and put her on the bed. With her free hand she pushed Anna's legs apart wider, and kneeled above her. "How deep?" She asked; baring her teeth in a feral smile.

Anna thought she was going to come there and then. She'd never thought her sister could look like that; but fuck she wanted to see that look again. "Deep."

Elsa carefully pushed in as far as she could go. "That deep?" Anna bobbed her head enthusiastically.

"Oh, fuck!" She yelled out when her sister plunged herself inside; and she grabbed onto blondes hair again. "Fuck! Elsa!" She screamed, as her sister pounded harder, and faster, and deeper – just like she'd wanted – and it was even better than she thought possible. She bucked and writhed - and she didn't care about the lewd noises her body was making; or that she no longer spoke any actual word – just grunts and groans.

When she felt the build-up to her release, she knew Elsa sensed it too - because her sister put every ounce of energy she had into fucking her until she screamed.

It hit her hard; and she wrapped her legs around Elsa's waist as she spasmed and she screamed out her sister's name.

Elsa fell on top of her with an exhausted thud, but Anna didn't free her sister from the binding of the legs.

"That can't happen again." The blonde stated after the energy had died down between them; and the fact that they were sisters came crashing back. She tried to pull away but the redhead refused to let her go. "Anna." She warned through gritted teeth.

"You can't make this – not have happened." She said; loosening her grip so that Elsa could remove her fingers from inside her. "It will happen again – and we both know it." She let her legs drop and her sister moved as quick as lightening - but didn't deny her bold statement.

She got up from the bed and pressed up against Elsa, who was standing by the door - no doubt to tell her to leave again – and then she kissed her; her tongue pushing inside, and the response from her sister was immediate. Elsa slammed her against the door – her knee going between Anna's legs, and the redhead groaned. She was still sensitive, but not so much that she could stop herself from grinding against the toned limb.

Then Elsa stepped away quickly, and squeezed the bridge of her nose. "Just…"

"…Go. Yeah, I know." Anna shook her head as she opened the door, and she stepped out into the hallway.

Well, that's just… Fuck She thought as she made her way into her room, and plopped down on her bed face first.

Her sister was going to be the end of her. She just knew it.

A/N: I don't write smut, or angsty stuff. I live in very fluffy world, with kittens and puppies and rainbows. This is so far out of my comfort zone, I don't even.

But I thought I'd try. And if it sucks, I'm very sorry.