Meredith looked up from her lesson plans a week later when there was a knock at the door. She frowned as she glanced at the clock, realizing that it was only eight. Derek was at work, and she'd eaten dinner by herself before settling down with some work to get done so she could be free for his day off on Sunday. She'd quickly realized that if she made the most of the time he spent at the hospital to work, they could take advantage of his time off.

"Lexie," she said as she opened the door. "What are you doing here? Is everything okay?"

"Just figured I'd stop by and say hi," Lexie giggled as she pushed past Meredith into the apartment. "Addison said that Derek and Mark are working tonight, so we figured we'd have a girls' night."

"Hi Mer," Addison smiled as she walked into the room. "Liz is on her way, she had to find something for Shawn to do. Apparently he's just as pathetic as the rest of those idiots we call our boyfriends."

"Girls' night?" Meredith repeated, still focused on Lexie's words. "What are you talking about?"

"Yeah, you know, gossip, junk food, chick flicks," Lexie said. "We used to do it all the time when we lived together."

"I guess," she smiled, looking up as Liz stumbled into the apartment.

"Sorry I'm late," she breathed. "You didn't start without me, did you? I had to take of something."

"We just got here," Addison replied. "Come on, Mer. We've got ice cream and chocolate."

Meredith stared at Liz for a moment before she stated, "You just had sex."

"What?" Liz cried, a slight laugh coming from her lips. "I…no."

"You so did," Meredith laughed. "Look at her hair."

"Definite sex hair," Addison nodded.

"You're sick," Liz stated, storming into the living room. "All of you."

Meredith giggled as she moved to sit beside Liz on the couch. "We're just kidding," she said.

"Well, I don't want to talk about my sex life with you," Liz blushed.

"I'll talk about mine," Addison volunteered. "Mark can surprisingly be very gentle, when he's not a wild animal."

"Hmmm," Meredith nodded. "Derek is completely amazing. But then again, a man of that size…can't really go wrong with that."

Liz winced. "That's my big brother you're talking about," she said.

"Sorry," Meredith giggled. "We can talk about your sex life instead."

"I don't want to," Liz insisted.

"Fine," Meredith nodded, turning to Addison. "Derek does this thing in the shower that drives me crazy. He makes me grab my ankles, and then he thrusts his…"

"Okay!" Liz cried. "That's enough."

Meredith and Addison turned to look at her expectantly. "Well?" Meredith prompted.

"Fine," Liz sighed. "Shawn's…well, he's amazing. And I don't have very much experience with other men, but the way that he makes me feel is just completely amazing."

Addison sighed as she leaned back into the cushions of the couch. "Yeah," she sighed. "I know what you mean. Mark can make me forget my own name."

"When we were in Italy the reception desk called up to ask us to kindly respect the stay of the other guests in the hotel and keep the screaming to a minimum," Meredith giggled. "That's when I first realized that Derek goes crazy when I tie him up."

"You know, Mark's never really been interested in that," Addison sighed. "Do you think if I let him tie me up first he'd be okay with it?"

"When I was with Mark…" Liz started before she quickly stopped herself, the other three women looking at her with wide eyes. "Oops."

"You slept with Mark?" Meredith asked.

"Well…yeah," Liz said. "All of us have. It's no big deal. He…taught me things."

Addison choked on her wine as she turned to look at Liz. "All four of you?"

"Wait a minute, Caitlin's slept with Mark?" Meredith asked.

"Who hasn't slept with Mark Sloan?" Lexie asked, speaking up for the first time.

"Um…apparently only me," Meredith replied. "Lexie!"

"What?" Lexie asked. "He came over once when you and Derek were dating the first time, and I was lonely, and he was just…there."

"I can't believe this," Addison groaned, burying her face in her hands.

"Maybe we should change the topic," Liz suggested.

"And never speak of this ever again," Meredith nodded. "Especially to Derek. I can't be held responsible for what he'd do if he found out that all of his sisters slept with Mark."

"Right," Addison nodded. "Although I gotta say…I should be given credit for finally getting him to settle down."

"Mark's always been a big softie," Liz giggled. "You're just the one who brings it out in him."

There was a long silence for a moment before Meredith asked, "What did we talk about before we had boyfriends?"

"Work," Lexie shrugged. "School."

"Hmmm," Meredith nodded. "It's weird. Derek and I have barely even known each other for a year, and for a lot of that time we weren't even together. But I can' even imagine my life without him anymore."

"He loves you a lot," Liz said. "I've never seen him this happy before, ever. And when you were broken up, he was completely miserable."

"I know," Meredith whispered. "I hate that I did that to him."

"But you love him," Lexie said. "That's what matters."

"You want to know a secret?" Addison asked, leaning towards Meredith.

"Always," Meredith smiled.

"Mark told me a couple weeks ago that he's going to try to be more like Derek," Addison giggled. "Because Derek's the kind of man who has relationships and as we just found out, Mark's the kind of man that sleeps with any woman who's willing. He said he needs to be the relationship type of man because he thinks that's what I deserve."

"Derek is amazing," she said softly. "More men should try to be like him."

"Alright, that's enough talk about the boys," Liz said. "Let's watch a movie and stuff our faces."

XXXXX

Derek sighed as he dragged himself into the apartment, exhausted after a long shift at work. It was five in the morning, but in that moment all he wanted to do was pull Meredith into his arms and sleep forever. He stopped briefly in the living room to look at the tangled mass of bodies on the floor, amidst blankets and pillows. Empty ice cream cartons littered the table, scattered with open DVD cases, an empty bottle of tequila, and a stack of pictures, presumably from their European vacation.

He shook his head as he moved into the bedroom, not bothering to turn on the lights as he stripped out of his clothes and slid into bed, pulling Meredith close and burying his face in her hair, frowning when he realized that she'd changed her conditioner from the lavender scent he loved so well to some kind of tropical coconut smell. He was definitely going to have to talk to her about that.

"Hmmm," he murmured, leaning forward to kiss her cheek. "Love you."

She sighed as she turned in his arms, burying her face in his chest. She felt different somehow, her body felt different, but he contributed that to the fact that he'd been awake for almost forty hours and wasn't thinking clearly. "You're home."

"I'm home," Derek nodded, not bothering to open his eyes as he felt himself already falling into the comfort of sleep.

"I missed you."

"Hmm…me too."

"We should…sex."

"Definitely sex," he whispered, eyes still closed as he reached under her shirt to cup her breasts.

"Oh," she moaned, pressing herself against him. "Mark…"

Derek froze, quickly withdrawing his hand as he slowly opened his eyes and reaching for the light. "Addison!" he yelled, reaching to pull the covers around his naked body.

"Derek!" she cried, pulling her shirt back down and turning to the other side of the bed. "Mer, wake up."

"What?" Meredith groaned from Addison's other side. Derek frowned, wondering how out of it he must have been to not realize that was an extra person in his bed.

"What the hell are you doing in my bed?" Derek demanded.

"You're supposed to be at work," Addison cried.

"Derek?" Meredith groaned, finally waking up. "Oh crap."

"Mer, what is she doing in my bed?"

"She has a name," Addison snapped.

"And an apartment," Derek replied. "With your own boyfriend."

"Fine," Addison sighed, climbing to the end of the bed and walking out the door, rolling her eyes as she did so.

"Mer, I'm sorry," Derek said, turning to his girlfriend as she looked up at him with an amused smile. "I thought she was you, you know I'd never…"

"I know," she nodded. "Personally I thought it was funny."

"You would," he rolled his eyes. "What was she doing here?"

"We had a sleepover," Meredith replied. "I said whoever was the drunkest could sleep in the bed with me. She won."

"Obviously," Derek sighed, pulling her close. "That was embarrassing."

"Baby, you've got nothing to be embarrassed about," Meredith giggled, reaching down to wrap her hand around his penis. "This is all man."

"Hmmm, and it's all for you," Derek whispered, pressing his lips against her neck.

"Good," she giggled.

"I love you."

"I love you too. I'm sorry there was another girl in our bed."

"You never need to apologize for that," Derek shook his head. "In fact if you want to invite Addison back in here…"

"You're an idiot," she rolled her eyes, rolling onto her back. "And it's not as much fun as it seems."

Derek was silent for a moment before she felt the sheets rustle and suddenly he was looking down at her. "I think I'm going to need you to clarify what you were just saying," he requested.

"Threesomes," she shrugged. "Not that exciting."

"You've…."

"One very drunken mistake during freshman year," she said without looking at him.

"Details," Derek begged. "Please, Mer."

She rolled her eyes as she turned onto her back. "What is this obsession guys have with girl on girl?" she asked.

"Was she hot?"

"I guess," she shrugged. "I don't really remember."

"We could get Addison back in here," Derek suggested. "Or Izzie."

"Seriously?" Meredith asked. "You want to sleep with Addison?"

"Well…no," Derek replied. "I want you to sleep with Addison."

Meredith stared at him for a moment before she nodded. "Okay," she said.

"You…wha…seriously?" Derek asked.

"You can invite Addison into bed with us," Meredith nodded. "But then it would only be fair that Mark get the same attention from Addison and I."

"How is that fair?"

"The same way it's fair that you want to sleep with one of my best friends," Meredith shrugged.

"I don't actually want to sleep with Addison," Derek said.

"Good."

"Only you."

"Mmmhmm."

"I have no complaints about the sex."

"You better not."

"In fact, I could show you right now how satisfied I am."

"Your sister's in the other room," Meredith murmured.

"She knows we have sex," Derek shrugged, rubbing himself against her. "She'll get it one day."

Meredith scoffed. "I'm pretty sure she already gets it."

"What?" Derek asked, pulling back.

"Crap," Meredith muttered. "Derek…."

"What did she say to you?" Derek asked.

"She's twenty three, Derek, did you honestly think she wasn't having sex?"

"She's my baby sister," he frowned.

"How old were you when you lost your virginity?" Meredith asked.

"Seventeen," Derek sighed. "But still…"

"So it's okay for you to do it as a teenager but your sister waits until she's ready to do it with someone she trusts and you go all caveman on her," Meredith said. "She's a big girl, she can take care of herself."

"You know something," Derek stated.

"You know what, suddenly I'm in the mood for sex," Meredith said, rolling on top of him and kissing him passionately.

"Who'd she sleep with?" Derek asked.

"Doesn't matter," Meredith breathed. "You're so hot, Derek. I want to feel you inside of me."

Derek sighed as he gave into the way her hips were rocking against his, knowing that he could always pry for information later. "You're in charge," he murmured.

"Of course," she purred. "I'm going to make you come so hard."

"God, Mer," he breathed. "Please…"

Meredith smiled as she slid her pajama pants off, knowing that she had successfully distracted him from worrying about stupid stuff. For now at least.