A one-shot written for the Requests Challenge II on xoxLewrahxox's forum. Thanks to Bangle-Baby for the great prompt.
The first part is only an introduction – the actual challenge entry is the second and biggest part. 965 words.

Prompt: Truth or dare with the Black sisters
Must haves: Something mildly inappropriate and at least one truth and one dare.
Mustn't haves: General stupidity. Try and keep it semi-canon personalities
Preferences: Less than 1000 words. And it should be funny. (Or at least TRY to be funny) =D
If you can...: Have some intense blushing going on. Poor Cissy isn't supposed to know about that yet.

Bellatrix Black yawned.

For, oh, let's say the two-hundred-and-second time that evening.

"Please, Bella," said Andromeda sarcastically. "There is absolutely no need to pretend to be having fun in my company. Don't make yourself overtired, you're being much sweeter than I deserve."

"Yes, that's what I think indeed," Bella replied, rolling over on the bed she was lazily reclining on. "What you deserve right now is an award for being the most boring person I encountered in a very long while."

Andromeda frowned. "Let me think," she said, "when was the last time we went in society with Mother?"

Bellatrix grinned toothily.

"About one week ago."

"That's what I thought."

Andromeda fell into a haughty silence then, finding a new determination to focus on her studying and ignore her sister, as said girl appeared willing to prove herself at least every bit as annoying as Andromeda was being boring herself. Which had been a false accusation to being with, she thought with a resentful sniff. She had tried to entertain her older sibling – but Bella couldn't seem to find entertainment anywhere but in that Lestrange boy's... bed... or anywhere they could go, really... lately.

She sniffed again at the thought.

"Merlin, Meda, have you run out of tissues last time you stole Celestina Warbeck's one and only album from the sniveling wimps you call your roommates, or has all the studying softened your brain to the extent that you actually can't manage a plain Accio?"

"Shut it, Bella," Andromeda shot.

"What a witty retort indeed. I wish you'd tell me how you actually come up with those, you know."

"What the hell is wrong with you?" shouted Meda, growing aggravated by the second.

"Oh, Andromeda said hell. My, isn't that shocking."

"Do you have a problem with the fact that you do have to spend some time with family once in a while, instead of fooling around with Lestrange?" she snapped.

Bellatrix rolled over again, so that they were now face to face.

"Do you have a problem with the fact that I do have a sex life and not you?"

Andromeda huffed angrily.

"What do you know about that?"

Bellatrix's intense stare made her blush and turn away, cursing violently in her head. Her sister hopped from the bed not three seconds later.

"I demand a Truth and Dare night. I see no other way to loosen your rebellious tongue with something other than goddamn Transfiguration."

Meda moaned with despair. There was no telling which would feel worst, a painful process of arguing or the self-disgust that came with obedient acceptance. But there was no arguing with Bella when she was bossy... or anytime at all, actually.

"I'm fetching Cissy," she said, standing up as well.

"Please do. But don't hope that corrupting her innocence will distract me from finding out every single embarrassing thing you've been shamefully concealing from your responsible big sister."

"I have no such thing."

"Truth or Dare, sister dear?"

Andromeda knew how dangerous her older sister she could be. Ages ago, she had decided of a few Rules of Behaviour around Bella, which had since proven necessary to protect both her pride or her safety.

Rule Number One: never let Bella know about the friends she wouldn't approve of.

Define "friends", whispered a voice in her head, and she mentally cringed.

She'd better choose the lesser evil – time to break Rule Number Eight. Taking the tiny vial of potion Bella was handing to her, she downed its content quickly. The syrupy liquid they called Motivating Potion tasted bittersweet to her wary mouth.

"Dare," she said, locking eyes with her older sister with cold, haughty confidence.

A slow, nasty smile spread over her sister's lips, and despite herself Andromeda looked away.

"Very well," Bella drawled. "You are to call a house-elf here to fetch us cocoa and cupcakes. While acting every bit like any proper young lady and self-respecting pureblood would, of course."

Andromeda slowly raised an eyebrow.

"That's it?"

Bella had a light, quite unpleasant laugh.

"No, darling. I want you to do it naked."

"You've got to be kidding."

Once again, Bella laughed airily.

"Oh, poor darling Meda. What dirty little secret could possibly have made you accept one of my infamous dares?"

Gently, she reached out and patted Meda's cheek.

"But you don't want the spots, do you?"

It seemed as if she could already feel the unpleasant tickle spreading on her face. Truth or Dare had always made her paranoid, but she did know that the potion would be effective, in the end – there was no bluffing it out.

She might not be as self-centred as her sisters proved, but she was not going back to Hogwarts with angry purple dots all over her face.

And to think that they say Muggles play the game too, only without potion.

Slowly, very slowly, Andromeda stood. Her robes, shirt and trousers were soon thrown to the floor, her hesitation gradually increasing. An absurd blush burning her cheeks, Meda fought with her bra for a while, numb fingers finally undoing the straps.

Her knickers followed.

As Meda made to sit again, Bella tut-tutted sharply.

"My, my, Meda. A young lady doesn't sprawl on the floor in front of her inferiors... She sits tall and proud... Chin up, back straight..."

"Boobs out..." Meda whispered in a sarcastic echo.

"You know me too well, sister."

Andromeda straightened up.

Even to her own ears, her voice sounded shamefully weak, little higher than a croak. "Kinky."

"Merlin, isn't that elf cleverly named."

Bella's comment didn't quite get lost in the sharp sound of the elf Apparating. Meda wished it had. She stared at a point on the wall, just above the tiny creature's ears as she spoke.

"Bring us cocoa. And cupcakes. Now."

"Yes, Miss Andromeda," the creature squeaked before Apparating away again. Meda reached for her clothes. Bella grabbed her wrist.

"Certainly our treats won't come up here on their own, don't you think?"

She straightened up again.

Tall and proud. Tall and proud. Tall and –

The elf's second Apparating startled her so much she couldn't help but jump and gasp. Her breasts swayed with the movement.

Tall and fucking embarrassed.

"Thank you, Kinky," she growled.

She'd never seen an elf look that red before.

"Cissy's turn," she spat, fumbling on the floor for her clothes. "Truth or Dare?"

"Truth," came the shy answer behind her.

As soon as she looked decent again, she turned to glare at her baby sister, whose cheeks were pink with nervousness – and despite herself, softened.

Cissy was just an innocent witness, after all.

"Have you ever been kissed?"

Cissy's flushed cheeks turned a slightly deeper shade of pink.

"Y-yes."

"Who?"

"Only one question, dear," interrupted Bella in a most annoying sing-song voice.

"Truth or Dare, Bella?" chanted Cissy while Meda took long, deep breaths and refrained from killing her older sibling.

"Truth."

"How many guys have you kissed?"

"It depends, honey. Kissed where?"

Andromeda choked on her cocoa. Cissy didn't seem to understand for about twenty awkward seconds, then:

"Oh."

"Protect your innocence, Cissy, hands on your ears. Bella, Truth or Dare?" Meda asked, eager for revenge.

"Calm down, you banshee and wait for your turn. It's mine right now – Cissy, Truth or Dare?"

"Truth," came Cissy's ever-careful answer while Meda silently seethed.

"Good girl. Have you ever had sexy dreams?"

There was a small silence.

"I've dreamt about Lucius before," Cissy admitted slowly, subconsciously touching her smooth cheek, as if to remind herself of the dreadful consequences lying would unleash upon her.

"What was he doing?" Bella pushed.

"One question!" cried Andromeda, but Cissy had already stuttered:

"Well... looking sexy, of course!"

There was another silence before the two elders burst out laughing at the same time, effectively turning Cissy's cheeks as red as Lilith Greengrass' most obnoxious lipstick.

Five minutes later, Bella brushed her tears away.

"Nothing to worry about on that side," she said hoarsely, and Meda nodded, still giggling. But then she suddenly sobered. Revenge was more important than petty fun.

"Truth or Dare?" she spat. Bella pondered before shooting:

"Truth."

"Have you ever shagged in a cupboard?"

Cissy's muffled gasp sent Bella into another fit of giggles, but Meda kept her focus.

"Yeah," she finally said. "But I'm not doing it at Hogwarts ever again."

"Why?" asked Meda, hoping for a juicy story of her sister getting caught.

Bellatrix didn't push for the one-question rule this time, snorting lightly instead.

"Spiders."

Narcissa gave a little scream at the thought, and Bella's smile widened slightly:

"Wouldn't want to mistake them for the more important hairy stuff."

"Bella!" shouted both her sisters in sync.

They were too disgusted to go on after that.