I woke up to a large rumble of thunder just in time to hear a gentle knocking on the door. I looked over at the clock. It was still the middle of the night, and there was a heavy storm outside. As I pulled myself awake, I saw my sister Olivia’s profile in the light of the open doorway. She was wearing an old pair of pajamas with cartoon characters on them. She’d outgrown them two years ago, but wouldn’t throw them away.

“What are you doing here?” I asked, still half asleep. She had something under her arm and I realized it was a rolled-up sleeping bag.

“Mom said I could sleep in here tonight,” she answered.

I stared blankly at her for a second, seeing her in the light coming off my computer monitor, which I had left on.

“The storm broke the window in my room and the rain’s pouring in there” she explained.

“Why can’t you sleep on the couch?”

“The animals.”

We have a menagerie of sorts; a chocolate lab, an Australian cattle dog/beagle mix, and two cats. They all sleep on the couch together in a big, furry pile. We’ve never had the heart to make them sleep outside.

Her voice told me how close to tears she was. It occurred to me the storm might have scared her. I rubbed my eyes and got out of bed.

“Of course you can sleep here,” I said. “How bad is it?”

She sat down on my bed. “The glass broke and the rain came pouring in on my bed and dresser and everywhere. Everything is soaked. Mom said we’d have to wait until morning to take care of it.” I could tell she was exhausted as well as nearly crying.

“Well, you’ll be fine in here,” I said. “It’s warm and dry in here. Let’s try to get some sleep.”

She started rolling out the sleeping bag.

“I’ll use that,” I said. “You take the bed. You need it more than I do.”

“I don’t want to kick you out of your bed.”

“I’m fine, really. After getting soaked you should get a good night’s sleep. Tomorrow’s likely to be hard too, with school and taking care of your room.”

“Thanks.” She climbed into the bed and was asleep almost immediately.

As I laid out the sleeping bag, I glanced up at my computer and was mortified. My room has always been my sanctuary, with Mom and Olivia rarely if ever coming, and I tended to forget I lived with anyone else when I was in there. I had been looking at porn online before I went to bed, and hadn’t bothered to close it when I was done. On the screen was a picture of a girl giving a blowjob. My desk is right next to my bed where I was talking to Olivia. There was no way she could have missed seeing it. I walked over to it and closed the browser. Before I turned off the monitor, I peeked down at Olivia to make sure she was asleep. Then I crawled into the sleeping bag and tried to forget my embarrassment.

The next morning Mom woke us up early and we went into Olivia’s room. The broken window would have to be replaced, and there was a lot of water damage. The carpet and the bed were both soaked. Olivia tended to leave her dresser drawers open, and water had gotten into most of her clothes there. Only the stuff in her closet off the floor was still dry. We taped plastic over the window and put the wet clothes in bags. Mom said she’d have to run everything through a laundry cycle. Then it was time to go to school.

Olivia and I are a year apart and go to the same high school, where I’m a sophomore and she’s a freshman. I have a permit to go from home to school, so I drive us back and forth every day. It’s a big school, and being in different grades we rarely see each other during the day. After school that day we met at the car to go home, and she was clearly upset. In the car I asked her what was wrong.

“I tried to eat lunch with Mandy and Cindy today.” I knew the three of them had been inseparable in middle school, but once they reached high school, the other two had dumped my shy sister to join a more popular clique of girls. It’d only been a couple of months, and Olivia was having a hard time making new friends. “Mandy and her new boyfriend made fun of me, and Cindy told me to sit somewhere else.”

“Ahh, they’re just playing dominance games, sis. Fuck ‘em.” Being shy myself I knew how lonely she must feel, but knew there wasn’t anything I could do to help except be sympathetic.

She glared at me, then smiled. “Nah, not my type. You can, though. Or maybe Cindy will give you a blow job, so you don’t have to fantasize while looking on the internet.”

I blushed. She wasn’t shy with me like with her friends, and clearly she had seen my monitor. As I turned the wheel, my shoulder complained and I made a sound.

Olivia looked up at me. “What is it?” she asked, concerned.

“Nothing. I’m just a little sore from sleeping on the floor last night.”

“I’m sorry. You should take the bed tonight.”

“No, I can’t have you sleeping on the floor after a hard day. It’s not too bad, I just slept in the wrong position.”

After we got home, I helped Olivia move some of her hanging clothes into my closet. Neither of us was a fashion freak, with tons of clothes, and we were able to cram it all in.

I sat in my computer chair.

“It’s sweet of you to share your room with me until Mom can get mine fixed up again. I know it’s always been your personal space, and I hate to impose on your privacy.”

“We both know a lot of brothers and sisters don’t get along,” I said, “but you know I love you, so it’s no big deal, okay? We’ll both just have to make some adjustments. It will be fine.”

She glanced at my blank computer screen for a second, and I remembered what I’d had up there the night before. I wondered if she was still thinking about that.

“I’m going to go downstairs and get a snack. Want something?” she asked.

I composed myself. “No thanks, I think I’m going to take a shower. Just make yourself at home and try to be comfortable.”

She left and I got into the shower. Olivia and I share a bathroom, which connects to both rooms directly. Usually when one of us is in there, we lock the other’s door. As I stood in the shower, I tried to relax and not worry about my sister’s problems or my own embarrassment from last night, and focused on letting the water relax my sore muscles. Still preoccupied, I got out of the shower, toweled off, and headed into my room to get dressed as I’d done a thousand times before.

I walked into my room and took a few steps before I froze. I had forgotten Olivia might be there, and she was standing in my closet with the door wide open, naked with her back turned to me. It looked like she was going through my underwear on a shelf in the closet. She was a little shorter than me, with long, straight red hair and soft, pale skin. Puberty had hit her hard, giving her an 18 year-old body when she was only fourteen. I’d noticed it before, and I know she got some grief for it at school, for being different from the other girls, but had never thought about her as a woman. Now, that was impossible. She had an hourglass figure, with a round, nicely shaped ass. As I froze, she turned around, holding a pair of my tighty whities, and saw me standing there, and for a moment we both just stood and stared at each other.

It was the first time I’d seen her naked since we were little, and the first time I’d seen any woman naked in person. She had round, firm breasts, with large, brown nipples that seemed to be pointing at me. Though I could have stared at the soft curves of her tits all day, my eyes were drawn down past her soft, flat tummy. Her pubic hair was as red as her braids. That hair was short and straight, though, seeming sparse, and doing nothing whatsoever to hide lush, thick pussy lips between her legs.

As I stared at her, I became aware that she was also staring at me. I realized I’d come in naked from my shower, and my dick was in full view, growing larger and stiffer.

She finally spoke.

“Sorry. All my panties were in the stuff that was soaked. I was just trying to find something to borrow.”

“Sure,” I said, my voice croaking. My cock was fully hard, now, pointing right at her. “Um ... sorry.”

Her eyes were glued to my prick as she pulled on my underwear. I stood there blankly, too overwhelmed to think of covering myself or retreating to the bathroom. She pulled a T shirt on, covering her boobs.

“These are a little loose, but should be okay,” she said. Her face was bright pink.

“I’m really sorry,” I said, finally covering my penis with both hands.

She put on some jeans and paused a moment, then slid past my naked body and left the room.

I got dressed and sat awkwardly with her during dinner, not saying anything. After Mom started cleaning up, I motioned for Olivia to come with me to the living room.

“Hey ... about earlier upstairs...”

“Don’t worry about it.” She was staring at the floor with a neutral look on her face. “We have to live together for now. Like you said, we’re having to make a bit of an adjustment.” She looked up at me and gave me a sweet smile. “Besides, it shouldn’t be a big deal if a brother and sister see each other naked.”

We watched TV for a while until after Mom went to bed, then left the couch to the dogs and cats and headed up to my room to get ready for bed.

“I usually sleep in just my undies,” I said, looking around.

“You don’t have to change anything for me,” she said.

“I’ll go use the bathroom so you can change,” I said.

“Okay.”

When I came out, she was in her old blue PJs again.

“Your turn,” I said, staring again at the spaces between the buttons on her pajama tops, stretched open from the shirt being too small. The openings to her soft skin underneath seemed larger than last night, but were still maddeningly small. I could just see where her chest curved softly into the side of her breast, and imagined the sight of her firm tits and big nipples again. As she walked past, her body brushed up against mine.

Normally when I was horny at night, I’d sit at my computer and visit some of my favorite websites and jerk off. That wasn’t an option tonight. I got into the sleeping bag and tried to clear my head.

Olivia came back in and saw me already on the floor. She turned out the light, leaving only the faint glow of my monitor, and climbed into the bed.

“It sure is cold in here tonight,” she said.

“Must be your broken window letting all the cold air into here through the bathroom.”

I got out of the sleeping bag and crammed a towel under the bathroom door.

Olivia watched me as I did it. “You really shouldn’t be sleeping on that cold hard floor, especially if you’re already sore.”

“And what kind of brother would I be if I let you sleep there?”

Olivia looked at me a moment and hesitated. “The bed is actually big enough for both of us.”

I hesitated at that idea, too. I still couldn’t get the image of Olivia’s naked body out of my head; sharing a bed might be a bad idea. On the other hand, the floor was cold and hard and my shoulder did ache. On the first hand, I owed it to her to be honest.

“If I get in bed with you I ... um ... well ... something might embarrass me.”

“You mean like after your shower?” There was no teasing or joking in her voice.

“Yeah.”

“I get it. You’re a guy. But it doesn’t scare me.”

“You’re kidding,” I said.

“No I’m not. And it would be warmer if we were both under the blanket.”

I felt my cock already getting hard. But she’d said it was okay.

“Alright, just for tonight.”

Olivia lifted the blanket and scooted over, making room. When I got in she was facing away from me, with just a slight separation between us. I could feel the heat coming from her body, but tried to put her out of my head.

“Goodnight, sis,” I said. “Thanks.”

“Goodnight.”

I had almost dozed off when Olivia said, “I’m still kind of cold.” She reached back and grabbed my arm and pulled. It was the most natural thing to scoot over and mold my body to hers. She pulled my arm over her and, suddenly, I was embracing my sister in bed. My cock, which had softened a lot, leapt back to full hard and pressed right against her buns.

I felt her warm body through her cotton shirt. With her hand over mine, she pulled it and nestled my palm on ... bare skin! It was her belly. Her PJ top had crept up, exposing her stomach, and she’d pulled my hand to lie there against her warm skin. For what seemed like a long time I just held it there, not daring to move, feeling her creamy skin just inches away from her breasts. I didn’t even breathe for fear of losing the moment.

Then I felt something else. My dick had settled between her butt cheeks, and our wiggling around had put the lump between her legs. It wasn’t hard to imagine that the tip of my cock was pushing my underwear to where another pair of my underwear covered her pussy lips. But what I felt was her kind of pushing her butt back at me.

I didn’t know what to do. She was the one moving, so I just lay still. It was hard, because I wanted to thrust my dick between her legs.

Olivia began to shift, and I felt a brief moment of panic thinking all was lost. Surely she’ll move away from me. Instead, she rocked her ass back and forth, pressing herself more against my hard dick. At the same time, she pulled my hand farther up. Now it was under her PJ top! She acted like she was just trying to get comfortable, but suddenly I knew it was more than that. My hand bumped into what had to be the lower swell of her breast. And I could feel her heartbeat. It was racing like crazy, but she was motionless, as if asleep.