I wanted to write one of these "Truth or Dare" stories, because they're the most fun for me to read! Hope this goes well! R&R but no flames please. :D Enjoy!

Characters:

Angelina: 16
Katie: 16
Alicia: 16
Ginny: 14
Ron: 15
Hermione: 15
Harry: 15
Luna: 14
Dean: 15
Seamus: 15

"We won! We won!"
Ron, Harry, Ginny, Alicia, Angelina and Katie leapt into the common room from the portrait hole and were greeted with applause from Hermione, Luna, Dean and Seamus. Luna had recently been transferred into Griffindor following her bravery at the Ministry of Magic, and had gone all out for the occasion and was wearing nothing but a Griffindor scarf and her school shirt.
"We won!"
"We know," Seamus said, and everybody laughed. The rest of Griffindor had gone home for the Easter holidays, and a 'friendly' tournament of Quidditch had been set up for those people staying behind.
"So let's celebrate!" Ginny yelled, and she and Luna jumped up and down in a circle, shrieking their heads off as Dean produced a crate of Butterbeer and packets of coconut ice.

They sat around the fire for a little while, Ginny flirting shamelessly with Seamus, who was enjoying the attention immensely and kept feeding her bits of coconut ice.
"So..." Katie said, eventually, after a lull in the conversation. "Who wants to play truth or dare?"

"Me!" Luna cried. The Butterbeer had taken an alarming affect on her, and she was becoming rather frightening.
"Me," Ginny echoed, and soon everyone had agreed with Katie's idea...

"OK, I'll go first, shall I?" Katie said, and everyone nodded. "K then. Hermione, Truth or Dare?"
"Truth," Hermione said, after some deliberation.
"Right... Have you ever had sex with anyone?"
"No!" Hermione blushed furiously.
"Ooh!" Dean cried. "She has!"
"I haven't!"
"No, she hasn't," Luna said. "Because we were going to, but we chickened out."
There was silence for about a minute.
"What?" Ron erupted, and Ginny let out a small yelp of shock as he banged his fist on the table. Luna blinked serenely at him and smiled.
"Yes," she said. "We were going to, but we didn't."
Hermione had gone magenta and was hiding under her long hair.
Harry laughed his head off, and soon everyone was. Apart from Hermione.
"OK, Luna," she said, "you do that to me, and I'll do it to you. Truth or Dare?"
"Dare," Luna said happily.
"I dare you to... erm... Ooh! Make out with Harry."
Luna leapt on top of Harry, straddled him, and stuck her tongue in his mouth. He didn't complain.
Everyone stared in shock as she stuck her hands down his trousers, and eventually he pushed her off, to rapturous applause and cheering.
"Is that how you make out with people?" Harry asked, slightly shaken, and Luna just laughed.

After the crate of Butterbeer was empty and the dares had progressed so far that Seamus was now uncomfortably massaging his arse and Dean was looking pleased with himself, Ginny had fallen asleep sprawled over Ron, who was eating peanuts, Hermione wasn't wearing a bra, Harry was unconcious, Angelina and Alicia were squashed in the corner, making out, and Katie and Luna were playing Wizard Chess quietly in the other corner.
"So," Luna said, waking Ginny up and making the girls kissing in the corner turn around. "Who wants to go next?"
"I do," Ginny mumbled. "I dare everyone to have a gang bang right here, right now."

Ron blinked down at his baby sister, and somehow, bent right down and kissed her on the mouth. Ginny mewled into his mouth and he pushed her down on the ground and gestured for Hermione to join him. She did so, sucking at his bottom lip as Ginny writhed under Ron's fingers.
"Aww man this is hot," Dean moaned, and got down on his knees to kiss Hermione's neck. Seamus groaned and leaned in to kiss Ginny, who was looking a little like a startled rabbit as the older teenagers kissed passionately above her.
Luna skipped into the pile, pinched Dean on the arse and then moved in to slide her hands up Hermione's shirt. Katie joined in with a quick kiss to Seamus's cheek, which turned into a make out session, with Ginny running her hands through their hair.
Alicia and Angelina just sat and made out on Ron's vacated chair, and Harry was still unconcious.
"Wake him up," Hermione moaned, "It will be way more fun."
Katie waved her wand somewhere in the direction of Harry, and he woke up to see a sweaty, making out pile of teenagers sprawled in front of him. "Ohh man, what did I miss?" he exclaimed, swooping in to hump Hermione through her clothes.
The common room was full of excited moaning and small shrieks from the girls as Seamus entered Luna, who was now completely naked and sucking idly on Hermione's breasts, Dean pushed himself into Ginny's arse, Harry did the same to Hermione, Alicia shoved her finger into Angelina. Katie sat back, grinning, then plunged a finger into what was closest - Luna's arse. She squealed and bucked her hips against Seamus', moaning, "Ohhh Katie, ohhh Seamus... oh, just fuck me more, that's it..."

"C'mon, baby, do me more..."
"FUCK ME! Ohh HARRY!"
"Oh SHIT! Holy crap... Ginny... Ginny."
"Fuck... oh Ali... oh shit this is good, oh shit, oh shit."
"I'm gonna..."
"Me too..."
"Aaaaaaaah..."
The last cry was one of pure delight, and Harry rolled away from Hermione to press his lips against Dean's; Hermione planted a light kiss on Ginny's forehead; Katie hugged Alicia and Angelina, who weren't quite finished; Seamus thrust into Luna one last time before pulling out and leaning his forehead against hers, moaning with relief and pleasure.

It was silent for a very long time, just laboured breathing and the occasional cough, or a flurry of movement as someone decided they wanted to make out with someone else.
"Well," Ginny said, tired. "That was fun."
"Yeah."
"Mmhmm."
"Wow."
"Right," Luna said, getting up and kissing Ginny on the cheek. "I'm going to bed."
Soon the small crowd in the common room disappeared, until only Seamus and Ginny were left. Seamus was asleep, his head dangling over the side of the armchair. Ginny watched him sleep and smiled lightly, crawled under his arm, and closed her eyes.