We settled into the sleeping bags, both of us on our stomachs, I had a book I was going to read but she just laid her head on the pillow watching me. I rolled to my back and held the book so the pages would catch the weak light from the battery lamp. My sister Helen flipped to her side away from me as if to sleep. We were on a family camping trip; mom, dad, me and my sister and our golden lab Screwball, AKA ‘Screw’. At that moment Screw was lying on my feet at the bottom of my bag. I tried to kick him off to move to Helen’s bed but he wouldn’t budge, my feet were pinned to the ground by the 70-pound dog. I was 18 at the time and my sister was quickly approaching 16 but since we only had two tents, I was forced to take Helen into one with me, our parents required their privacy. This had been the sleeping arrangements for years and they gave no thought to the fact I was pretty much an adult. I was going to have to spend four nights with my baby sister in the same space, I would have to be damn careful if I jacked off.

We were in the mountains of Western Oregon. We planned on hiking some of the many mountain trails, kayaking and fishing on the Umpqua River. Our stay would be four days and nights. Dad had his camera with three various sized lenses hanging from lanyards around his neck, he looked like a Japanese tourist. I wore a heavy fucking backpack with power snacks and drinks while mom and Helen got to enjoy the day unencumbered by anything but Screw’s tennis balls which they threw as we hiked. After setting up camp and settling in the first night, we could concentrate on the days coming. That was the night Screw told me ‘screw you, this is my bed’.

The next day, the first full day, was spent hiking, we might have covered 15 miles of hills and valleys following a couple of the popular trails and met several other hiking groups along the way. By the time we returned to the camp my legs were straining, I was tired from lack of sleep, I was ready for some down time. It wasn’t full dark when we got back to the campsite where mom and Helen cooked a campfire dinner then dad retrieved some beer from a cooler in the back of the truck. Neither my sister nor I refused when he offered us a bottle, Mom tried to object “Goddamn it Roy, they aren’t old enough.”

“Ah piss Margie, it’s been a long hot day, we could all use one.” I wasn’t a stranger to beer but I wasn’t sure if my sister had tasted any before. When she tipped the bottle and sucked down two quick swallows, I knew, she wasn’t virgin to beer either. The Milky Way was brilliant in the night sky when we went to the tents. I had to stay out until my sister changed into her sleep wear then she invited me in. I wasn’t so damn modest so I stripped to T and shorts then slipped my PJ pants on while my sister tried not to watch. She didn’t try very hard, she kept glancing at me as I changed. Screw immediately took his place in the middle of my bag and refused to move. As Helen laughed at my efforts to move Screw, the fucking dog groaned contentedly and rolled to his back. He wasn’t about to give up his space easily. I laid on the bag and tried to pull it over me but got only half covered, my ass was sticking out in the night air which was getting colder. I flopped and flipped and tugged but couldn’t get any more cover than what Screw allowed. My sister was lying comfortably on her stomach watching me with undisguised amusement while I got frustrated with the sleeping arrangements.

I gave up trying to get completely covered and lay quiet with my left side getting cold, my toes were numb. Helen had gone to sleep, she looked so peaceful, so warm. Our bags were not mountain climbing bags; narrow, down stuffed coffins, but larger; large enough for two if the two didn’t mind some body contact during the night. Fuck it, I was cold, the dog owned my bed so I crawled across the small space between the bags then lifted the top of Helen’s and carefully laid beside her. She rolled to her side away from me so I had room to lie on my side behind her and pull the cover over, we were back to back. Ah, that felt good, I was super tired and the warmth of the bed lured me into a fast, deep sleep.

Hands pushing on my back woke me up. I opened my eyes and looked out the small net window over my head, it was not full daylight, but quickly dawning. The hands on my back pushed again, with more urgency, I rolled over to face Helen. “What the hell are you doing in my bed?” was the first thing she said.

“I was cold.”

“You were cold so you think that’s a good reason to sleep with me!?”

“Shh, you’ll wake mom and dad.”

She toned down the volume “Get out, god, I have to go pee and you’re in the way.” Screw came alert, rose from his (my) sleeping bag and stuck his big nose in my face, he was ready for the day too. Crap. I threw back the top cover and stood, Helen quickly followed then slipped out to go pee somewhere while I changed back into my clothes. Screw followed my sister.

The day passed with more hiking and a short, fun, run over some Class II rapids in our inflatable kayaks. That evening after dinner and another cold beer my sister and I returned to the tent. Screw didn’t hesitate to stake his claim to my bag, directly in the middle. Some fucking weird law of physics about dogs lets them gain weight when they lie down. The normally 70-pound Lab weighed about 150 pounds when I tried to move him. After a short tussle I gave up and told Helen “I’m with you again.”

She looked at the dog then at me with amused eyes, “I don’t think you have a choice, turn your back while I change.”

She was behind me, asleep I think, but I wasn’t. The feel of a girl’s ass pressed against my back was really starting to stir my balls. My cock elevated to ‘proud’ and my nuts were tingling. I tried my best to ignore the cause of my growing arousal but my sister was too near. Lying with her was causing a storm of immoral thoughts and delightfully nasty ideas as my balls began to ache. I was beginning to overheat. I kicked the cover off my legs to cool off and just as I did Helen rolled completely to her other side and threw an arm over my waist. She was lying against me, her tits pressed on my back, her groin fitted against the curve of my ass. I damn near climaxed when the fingers on her hand flexed against my stomach and the soft warm breath from her nostrils wafted on my neck. “Are you awake?” I whispered. No answer, and the deep even breath on my skin let me know she was still asleep.

I reached over my back and put a hand on her hip then gently pulled her even tighter against me, I could feel her pubis rubbing on my butt. My cock thumped and spit a bubble of pre-cum into my shorts. Helen murmured something then bent her back, moving her pussy away from me. When she did her head pressed against my ear, her knees touched the back of mine. I could feel the tips of her tits heating my shoulder blades.

I lay still but my heart was thundering, my heated blood was warming the entire tent. Helen hadn’t moved for a few minutes then she shifted slightly away and went to her back. I took advantage of the move and rolled to face her. Her eyes were closed, her chest rising and falling evenly, she was still out. Driven by the hormones flowing full flood in my veins, I put a hand on my sister’s leg just over the knee. She didn’t object so within seconds I eased it up until the edge of my hand pressed her body at the junction of her legs. Helen rolled her head to the right, away from me, then her legs moved further apart. Encouraged by her move I put my hand over her pussy, the cloth of the pajama pants was warm and damp, and getting warmer. I don’t know if it was because of the heat I was radiating or it was her, but the temperature in the sleeping bag rose another 20 degrees. I rubbed my sister’s sex lightly which caused her hips to shiver. When she reacted to my touch like that I was lost, I was going to fuck her even as she slept.

I carefully moved my hand to her stomach, over the band of her pants then eased my fingers under the elastic. I pushed my hand into her panties then down and through her soft pubic hair until I was again covering her slit, only there was no material between her and my fingers. I flexed my long finger then stroked Helen from ass to clit. She gasped lightly, rolled her hips then let her breath out of partially open lips, my erection damn near split open with the heat and pressure. Slowly I moved my fingertip in circles as I pressed between the lips of her pussy until I felt the opening of her body, she was warm and wet, I easily slid my finger into her to the second knuckle. I began to finger fuck my little sister and her legs moved even further apart.

I stroked Helen and she was warming, her slit was getting wetter and hotter, the puffy pillows of her pussy were growing softer. My sister humped her hips, moaned, then put a hand over mine and pressed it closer to her body. She rolled her head to me and half way opened her eyes, her lips parted slightly as she puffed short sips of air. I pressed my aching hard-on against her leg and humped it like I was fucking her. Helen’s eyes flew wide with surprise and her lips formed the silent word “NO!” She gripped the hand between her legs and jerked it out of her pants then rolled away far enough that there was no more contact between us. Rebuked by Helen for making a pass at her, I rolled away then poked my overheated cock into the cool night air. I gave her enough time and space to go back to sleep before I dared whack it. Even with the pressure off I worried like hell she would tell our parents what I did. Screw never opened an eye.

The next morning my sister didn’t start a war or say anything to me or dad about me molesting her while she slept. After couple of hours in her company, I my frayed nerves calmed and I became comfortable around her again. The day passed, I spent much of the time catching and releasing several large trout. Helen and Screw roamed the nearby hills and rocks, mom and dad went for a hike. It was a hot mid-afternoon when Helen and the dog came back to where I was fishing. The big yellow lab didn’t ask permission or hesitate to leap into the river pool I was fishing in as my sister complained “I’m hot, I wish I brought my swim suit.”

“You can go wading, that should cool you off, at least your legs.”

Helen thought a moment then said “I want to get all wet. I’ll wear my bra and panties but you can’t stare or make fun of me.”

“I won’t, in fact, I’ll get in the water too, in my briefs if that’s okay.” She didn’t answer but started unlacing her hiking boots. As my sister undressed to underwear, I did the same.

Even though I’d been in bed with my sister twice and damn near raped her the night before I’d never seen her without clothes before. Being in the final phases of puberty, her body was a vista of soft curves, firm fleshy mounds of tits and ass, she glowed with vitality. She had morphed from a cute little girl to a pretty teen and at eighteen years old, pretty teen girls attracted me like fucking magnets. Helen was no different. I watched as she stepped into the water wearing just brief panties and a soft full bra, and my nuts vibrated. She turned to me and asked “Are you coming?”

“Not yet but damn near.”

“Huh?”

“Yeah, I coming” I said as I pulled off my shirt.

We splashed and played in the refreshing water, throwing the ball for Screwball, laughing and bantering, just having a fun sibling episode. Neither of us was self-conscience about frolicking in our underwear, it became a non-issue as soon as we were in the water. After a half hour or so Helen got out of the river then went into our tent, moments later she stepped out to hang her delicate wear on a tree branch. She was nude. I stopped moving and stared at my sister, she turned and saw me looking at her, flushed pink in the cheeks then scuttled quickly back into the tent. My cock flared with carnal interest. The dog leaped at the ball, reminding me he was still there.

That was the last full day at the camp, we would be leaving in the morning. After dinner mom and dad shared the last of the beer with us while they showed us dozens of pictures taken on the hikes. A little before ten that evening, they bid us good night and went to rest. Helen and I were left to stare at the stars. We ignored each other while we tried to get signals on our smartphones but it was a wasted effort. In three days, we hadn’t been able to connect with friends or Facebook. My sister gave up and said good night then retreated from the moonlight to the tent. Me and Screw stayed outside, giving her time to get settled in bed. It was well into the late hours when I finally went to join Helen. Screw took up his position in the middle of his sleeping bag and challenged me with his eyes to push him away. I didn’t even try. I changed to my sleep wear then went to bed with my sister. I turned off the battery lamp before I crawled into the bag next to her so I didn’t see Helen as I lay behind her. When I was on my back in the bag she shifted slightly, bent her leg at the knee which put her foot on my lower leg. Her toes twitched against my ankle which caused a thrill to shiver up my leg. Helen turned over to face me, looped an arm over my chest and snuggled to my side. Her breasts were pressed on my shoulder, her legs rubbing mine. My cock exploded in length and girth, I started to panic because if she didn’t move, I would start something she might not like again. I reached across my body to push her away and when my hand touched her, it was bare skin I felt. My head jerked back, I squinted in the dark at her then moved my hand from her shoulder down her side. She wasn’t wearing anything. Helen was naked under the blanket. My heart started tripping, my face flushed hot, my cock bobbed with each quickened heartbeat. Just as my hand slid over her leg, she turned her face up then nuzzled my neck. Her hand moved from my chest, down my stomach, under the band of my pj’s then her fingers encircled my erection. She started rocking her hips, rubbing her groin on my thigh as she managed to push my sleep pants down, off my waist.

I rolled to my side to face my sister and she pulled me closer by my erection until it touched the junction of her legs. The end of it slipped between the hot wet folds of her sex then I felt the head enter her. Helen held it tighter then started rolling her back, pumping her body on the hard muscle between her legs. She gasped softly, moved her hand and put it on my hip. She pulled me even closer which forced my cock deeper into her. I pushed against her making her go to her back while pinned to me by my cock. When I was over her, she spread her legs as far apart as she could in the sleeping bag then put her arms around my back and pulled me down. I was lying on her from groin to breasts, she puffed softly in my ear then began to move with me. Less than a minute after going to bed with Helen, we were fucking.

What we were doing was not only a fantasy come true, but also a surprise. Helen had stripped nude then waited in the tent until I came to her. She knew that Screw would commandeer my bed and I would be forced to share her bag with her again. My sister got hot for me, waited, then without saying a word, invited me to have sex with her. I pushed up on my arms, looked down on the pretty fifteen-year-old girl and smiled my enjoyment as I plunged down and in. My body slapped hers too loud so she put a hand between us to stop what I was doing. We had to be quiet, the fabric walls of the tents were not soundproof, something we learned long before. Helen put a finger to her lips to schuss me then smiled, humped her back and I started fucking her again, only softy, quietly.

She was warm, soft, tender and deep. We were both heating up more as my cock slid in and out of her easily. I pushed into her as far as I could and held still as I twitched my cock, causing her to gasp and moan softly. The quiet outburst wasn’t quiet enough because just after Helen grunted, we heard our mother call out from the other tent “Helen, are you okay, what’s wrong?”

We froze, afraid to move, my erection was lodged in her, her legs crossed over mine. Helen took a breath then answered “That goddamn dog is lying on my legs, I’m trying to kick him back to Mason on the other sleeping bag.” With that one statement Helen said two things, she covered for the noises and hinted I was in my own bag.

Just as our mom said “Okay, good night dear” I pulled out of her tight pussy and erupted. I gushed cum into the crack of my sister’s ass, down her butt to the bag. When I was done convulsing, I lifted off her and went back to my side.

Helen was grinning, her eyes sparkled in the dark, she whispered “You messed up my bed.”

“Better than in you.”

She put a hand on my cheek and pulled my face close enough she could breathe in my ear “Yeah, maybe, but I’m not done, I hope you can get it up again.” Jesus, this was a sister I didn’t know, but sure as hell was one I was willing to learn about.

I didn’t answer verbally, I reached between her legs then started rubbing her clit with two fingertips. Her hot button swelled immediately, she widened the gap between her thighs and began to hump her back. I could feel her getting ready to climax but didn’t want her to start yelping so I felt around in the dark until I found a sock. I put it to her lips, she opened her mouth and I stuffed it in. Moments later Helen was staring at me with wide, passionate eyes and a sock jammed between her teeth when she launched into the clouds on a trip of ecstasy. The rush of air through her nostrils was the only noise she made.

We couldn’t talk; I couldn’t ask her why she came on to me and let me screw her but I sure as hell wasn’t going to complain. As her chest rose and fell while she relaxed on the downside of her orgasm, I put a hand over the firm mound of her left breast. Helen pushed the sock out of her mouth with her tongue then put a hand over mine and pressed it to her breast, she put her eyes on mine then smiled. I tweaked the nipple which caused her lids to flutter. I played with my sister’s tits while she slipped a hand over my prick and began to encourage another session. She and I played, felt and got hotter until my erection was what we both wanted it to be. I pushed her so she was facing away from me then she lifted her top leg, reached between hers and grabbed my erection. Helen pumped it three or four times then rubbed the head against her pussy. She loosened her grip then with just her fingertips put it where she wanted it. I slipped into my sister’s tender wet tunnel and began to fuck her again, totally silent, totally lost in her hot velvet pussy.

Maybe eight or nine minutes after I started fucking her, Helen started flopping a hand around, looking for something in the dark. I paused and pulled out then whispered in her ear, “What?”

I barely heard the answer “The sock, where is it?” It was lying next to my head so I took it and handed it to Helen. She jammed the sock in her mouth again then arched her back, pressing her ass against my groin. I slid my erection back into her then heard the muffled sigh as she took every inch I could give her.

My muscles were tensing, my cock was bloated with semen, I was ready to erupt. Helen’s body was flowing in waves against me, her pussy flooded with wet heat. When I pulled out of her she pushed back on me, trying to keep me imprisoned in her body. She felt me pulling back but put a hand on my hips and pulled me tight against her. She didn’t want me to pull out so I breathed a warning close to her ear “I’m gonna cum.” She didn’t say anything, she couldn’t with the sock in her mouth, but the hand on my ass gripped even harder. The strength of her grip as she held me let me know I didn’t have to pull out. My erection clenched then I started cumming in my sister. She must have been teetering on the edge too because when I slammed tight against her she groaned and started vibrating from legs to head. My sister came in sync with the erection pulsing in her.

Just as she stopped shaking, we heard “Helen?”

Helen jerked the sock out of her mouth and answered as calmly as she could “That fucking dog won’t move dad.”

We heard a soft chuckle “That’s no reason to swear like that. Try to get some sleep.” My relaxed prick slipped out of my sister’s hole, followed by a wash of semen. My sister turned over, put an arm over my chest and hugged me while her breathing slowed to normal.

I fucked Helen twice more that night and we managed to keep from alerting our parents to what we were doing. The dog slept carefree on my sleeping bag, my sister and I didn’t get any sleep at all. Days later I overheard our father talking to our mother, “When we go camping with the kids again, we should take another tent or sleep men in one, women in the other.”

“Why?” she asked.

“Because I found a large stain in the bag Mason slept in, he either had a wet dream or masturbated. That’s normal for an 18-year-old, but we should keep a distance between him and Helen from now on, she doesn’t need to be exposed to his nighttime activities.”

I smirked, because he was one camping trip too late.

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