Sister in Law Backseat Pt. 03

This is the third part of a series. Please read the previous installments for context for this story.

I love hearing from you and feedback is always appreciated. Enjoy!

Chapter 3

I had always loved to visit my wife's family cabin. Her grandfather had bought and built it when he was a young man so it was a generational thing, with the expectation that my wife and her younger sister would inherit and share it eventually.

It was small and had not had the million dollar rebuild that most cabins on the small lake had. It was rustic and simple but it had two bedrooms, a cot in the living room, an outdoor shower, a working plumbed toilet-thank god-, a simple boathouse on a dock and a strip of sand beach. It was on a kind of cove so there were no neighbors at that end of the lake making it very secluded.

Any chance we had to get up to the lake, escape the city and relax I was always eager to take. This weekend, however, I was dreading it because it wasn't just going to be my wife, Kristen and I. Her 19 year old sister, Jenny would be coming too.

Two weeks previously Jenny had jerked me off in the backseat of a car with my wife sitting in the front street. It had been wonderful but a terrible mistake. My wife and I had been married for 11 years and I loved her. I had no intention of fucking that all up but...Jenny with her full tits, young body, curly brown hair and cute freckles across her button nose was hard to resist.

Jenny and I had been sending each other images and videos since the eventful night in the car. She would send me nudes and videos of her fucking herself and I would send photos of my hard cock. She would call me and moan into the phone while I jerked off in the bathroom at work. It was exciting and sexy and the worst thing I could be doing. But at least, thus far, it had been limited to online.

Now she was coming to the cabin with us and I couldn't see her leaving me alone.

I tried to call off the trip. I claimed I had too much work to do but Kristen would have none of it.

"Mark," she said, finally angry with me. "We are going to the cabin and there is no way around it. You will relax and have fun! Also," she added, "you promised my dad that you would strip and re-paint the boat. No one can take it out if you don't do that!"

I had no choice. I was going to the cabin.

++++++++++

It had been a hot summer with temperatures staying steady over 30 degrees celsius and very little rain. It was honestly going to be great to get out of the city.

Because of my wife's motion sickness I was driving our car, an Audi Q3, and we swung by her father's house to pick up Jenny.

I was waiting in the car as she came jogging up carrying her bag. It was a sight that made me groan inwardly. She looked amazing.

She was wearing a loose, mid thigh length skirt and a yellow, string bikini top. Her breasts, 36D, were barely covered, and they swung magnificently as she moved towards us smiling.

"Jenny!" My wife said as she got into the car. "What are you wearing?"

"Oh, I'm going straight into the water when we get there," Jenny said. "I wanted to be ready."

"It'll be cold in the car on the way up," my wife said. "You know I'll need the AC on so I don't get sick."

"I'll be ok," Jenny said offhandedly. "Hi Mark! How have you been?"

She knew exactly how I had been. Horny and hard since I had last seen her. I was jerking off more at 40 than I had since I was 15 because of her.

"Good, not too bad," I said, tearing my eyes away from her perfect breasts to meet her eyes. She was grinning and the eyes danced with mischief. I knew I was in for trouble.

It was about a two hour drive to the cabin and Kristen,like she always did, quickly laid her head against her window and went to sleep, the only reprieve she had from carsickness.

Jenny was in the back seat, with headphones in, scrolling through her phone for the first half an hour or so, as we left the city. I was able to look into the rear view mirror and see her and spent probably too much time glancing into it, watching her.

Eventually she looked up, then leaned between the seats and checked to see if Kristen was asleep. Once she was satisfied she was she reached up and angled the rear view down more so I wasn't really able to check traffic behind me. The focus was on her sitting there.

She slid into the center of the bench seat and grinned wickedly at me. I glanced at Kristen and shook my head at Jenny in the mirror. This was about to be a mistake, I knew.

She ignored the head shake and slowly traced her finger along the edge of the fabric of her bikini top, slowly running up and down the line where it met her exposed flesh. I could see that her nipples were hard, little nubs that tented out the yellow fabric. We could say that it was from the AC, but knowing her, it was my eyes on her body that caused them to harden.

She locked eyes on the mirror and smiled slyly as she pushed her finger under the bikini top and then tugged it to the side, freeing her brown nipple and areola. My cock had already fully hardened by this time and I let my hand drop to my lap, lightly gripping myself lthrough the fabric.

She slowly traced her finger around the hard nipple before gripping it between her finger and thumb, tugging on it. Rolling it in her grip.

Her lips were parted slightly and I knew, from our online dalliances, that she was enjoying herself, making herself very horny. I was lightly squeezing myself, not wanting to go too far. I didn't want to wake my wife or cum in my pants, making a mess.

Jenny exposed her other breast and was now playing with both of her nipples, teasing, tweaking. My eyes darted from her to the road to keep from crashing and back to her. Her head was tilted back now, enjoying what she was doing to herself.

One hand left her chest and she slid it over her smooth belly to her skirt which she lifted up. Under I could see the matching string bottom to her bikini, knowing what that cloth hid. A perfect pink, shaved pussy. I had seen many photos and videos of it and, on that ride a couple of weeks before, had my fingers inside of it.

She pulled the fabric of the bottoms to the side giving me an in-person view for the first time in a long time. She was perfectly shaved, and she parted the glistening lips with two fingers to show me how wet she was. Her clit was hard and she began to rub it. I could hear her make a small moan and looked over at my wife to confirm that she was still asleep.

We continued like this the rest of the trip. Her slowly, sensuously playing with her hot young body, putting on an extended show for me. I gripped myself and gently squeezed and tugged. Keeping myself under control. By the time we pulled into the rutted dirt road that led to the cabin my balls aches for release.

A jolt from a dip in the road that I didn't notice because my eyes were locked on the young thing in the backseat shook us all. Kristen moaned and opened her eyes looking around confused.

Jenny in the back, quickly shoved her tits back into her bikini and pulled down on her skirt, managing to cover herself before my wife turned and looked into the back seat.

"Oh, sorry Jenny," Kristen said. "The ride must have been so boring. I just can't keep my eyes open."

"I know," Jenny said. "It's ok. I kept myself amused."

I rolled my eyes at that.

We pulled up to the cabin and while my wife got out I arranged my still-hard cock so it was poked up, held in place and hidden by the waistband of the shorts I was wearing.

"I'm bursting!" Kristen exclaimed and began hurrying to the bathroom inside. "Mark can you start unloading?"

As soon as she got through the door, Jenny moved, quick like a viper, to stand in front of me.

"That was crazy, Jenny," I started to say but was cut off when she grabbed the sides of my head and pushed her lips against mine, kissing me. Without thinking I opened my mouth to her probing tongue and we kissed for a moment. it occurre to me, through a fog of lust that came over me that this was our first kiss.

She took one of my hands in hers and moved it up to her breast. I closed my hand around it, feeling the hard nipple under my palm. I groaned into her mouth as she reached forward and gripped my cock through my shorts.

I was breathing heavily when she suddenly stepped back.

"It's good to feel your hand on me again, daddy," she said. "And don't you call me Jenny when Kristen isn't around. I want you to call me princess."

"Jesus Christ," I said. "That's a mistake. We can't be doing that!"

She just laughed and stepped against me again. I could feel her young, firm breasts press against me. Instinctually I placed my hands on her round hips.

"Later," she said quietly, "when you fuck my sister I want you to imagine me. Make her cum loud so I can hear it. I'll be in the next room playing with myself."

Then she stepped away from me and began jogging down the sloped path that led to the water, pushing her skirt down as she went. I watched her round ass bounce as she ran away from me.

"Going to jump in the water!" She called over her shoulder as she went.

I sighed, readjusted my hard cock and began unloading the car.

+++++++++

It didn't take too long to get settled in. The cabin was mostly stocked with essentials. We had brought food for grilling and plenty of beer and wine. In less than an hour we were all sitting on loungers by the water, enjoying the heat. Later, we had decided, we would play some cards and eat.

Jenny behaved herself, mostly. Beyond looking like a fuckable sexpot she didn't make any moves on me for the evening. Occasionally she'd meet my gaze and hold it for a moment too long but not in a way that Kristen could suspect anything.

Eventually, after a few drinks, some cards and laughs we decided to call it a night. Kristen got up to get ready and Jenny leaned across the table.

"Remember, Daddy," she whispered. "When you fuck her, that's me you are fucking. Make it a good one."

Then we went to bed. We had the larger room with the queen bed and Jenny had the adjacent, smaller one. The bedrooms shared very thin walls. It wasn't hard to hear what was going on on the other side so usually Kristen and I, when we made love with other people there, were as quiet as possible.

That night, having been driven crazy by Jenny's earlier teasing, I was hard as a rock when we entered the room. Kristen was wearing an oversized tee shirt and panties. I took a moment to admire her. She was 38, but she still looked good. Her breasts had not sagged much, and she kept herself in shape. I knew I was lucky to have her and was a fool to risk her for her younger sister.

Still, it was Jenny on my mind when I reached for my wife and pulled her against me, pressing my hard cock into her stomach.

"Mark," she giggled, "careful. Jenny might hear."

"It's ok," I said. "I saw her put earplugs in when she went to bed." This was a flat out lie but I didn't want Kristen to hold back.

I picked her up and dropped her on the bed as she laughed. I gripped each of her thighs and pushed them apart, putting my face in her crotch and inhaling the scent of her sex. It was good but I remembered the slightly different smell of Jenny on my fingers after I had fingered her.

I gripped the hem of the panties and drew them down quickly making Kristen gasp. I dove in before she could say anything and my tongue lapped along her pussy, over her vagina and swirling around her clit.

One thing about being married so long, I knew everything about getting Kristen off with my mouth. I had studied the subject well and was quickly licking and sucking her clit while two of my fingers stroked her pussy, digging in and rubbing her g-spot.

It didn't take long before she was gasping for air, moaning and whimpering from my mouth. She had her fingers in my hair, holding me in place as her hips rose against my tongue and mouth, pushing my fingers deep into her.

I took her to the very edge of her orgasm. Concentrating on her pleasure actually drove Jenny from my mind temporarily, so focused i was on my wife at that moment. Then, as I felt her breath catching, knowing she was on the very edge, I abruptly stopped.

I held her there as she gasped.

"Mark," she said, frustrated. "What the fuck. Keep going. I'm so close!"

I ignored her and slowly stroked my fingers I her, keeping her just on the edge.

"I want to be inside you," I said, not shouting but loud enough that I knew Jenny could hear if she was listening.

"Ok," Kristen gasped. "Get up here."

I continued to stoke and occasionally lick.

"I want you to ask me nicely," I said with a smirk.

"Oh fuck, Mark," she said, starting to whine, "c'mon and fuck me."

"Say please."

She paused. Stubborn. But finally she said it.

"Please."

"Louder,"'I demanded.

"God damn it! Please."

"I can't hear you."

"Mark! Please fuck me!"

It was loud enough I figured. I moved quickly up her body and aiming at her sex sank into her in one thrust.

She had started out trying to be quiet but that was done now. She had long forgotten that as I slammed myself into her again and again. She moved from moaning to squeaking to demanding loudly for me to fuck her hard.

It was an amazing sex session and it should have been more than enough for me but as my cock sank into her again and again I imagined it was Jenny's tight cunt wrapped around me. My eyes were closed but Jenny's cute face was the one I saw in my mind.

Finally I felt my climax building and I sped up even more. Kristen was repeating "oh fuck, oh fuck," over and over again. I couldn't hold back any longer and my fingers dig into Kristen's hips, my back arched and I released into her, moaning, collapsing on her.

After I caught my breath I rolled off and lay on my back, my cock, wet with my cum and her juices, still twitching.

"Wow," Kristen said, laughing softly. "That was amazing. I hope Jenny didn't hear."

I shook my head.

"I need some water," I said and got up, pulling on my shorts. I left the room and walked towards the kitchen. As I passed Jenny's room I saw the door was open. She was sitting up in bed, and our eyes locked. She has raised her arms and mimed a light golf clap. I grinned and made a courtly bow and got my water before heading to bed and collapsing, falling asleep within minutes.

++++++++

The next morning I woke last. I could smell coffee and bacon, my two favorite smells in the world. I groaned and rolled out of bed, pulling on shorts and a tank top and joining the girls at the table.

"Good morning," Kristen smiled at me. She was always happy the morning after a good fucking. I smiled back then glanced at Jenny. She was also smiling. A secret smile that only the two of us understood.

I grabbed my coffee and mused that I might go for a run.

"Nope," Kristen said. "You know you have to scrape and paint the boat. No fun until that's finished!"

She was teasing but she wasn't wrong. It was a big job that needed to be finished and if I could get away with skipping it I would.

The girls had decided to spend the day on the beach in the sun. I grumbled how that must be nice but, in reality, I welcomed the reprieve from Jenny's looks. She was very difficult to ignore.

Today's bikini was even skimpier than yesterday's, but this time in white and blue stripes. Her assets jiggled each time she moved and I had a hard time keeping my eyes off of her.

I grabbed a big bottle of water and while the two of them headed to the sand I grabbed my tools and went over to the boat.

It was an old boat, 15 feet long and made of wood. Last time we had come down I had hauled it out of the water, removed the engine and flipped it onto a couple of sawhorses. The paint was still the original and it was peeling and discolored. If it wasn't taken care of soon the boat would begin to rot away.

I put in headphones and took my hand held scraper and cursed not having some kind of power sander and began to work. It was a hot morning and before too long I was sweaty and uncomfortable. I peeled off my tank which was dripping with sweat and got back to work scraping away the peeling paint.

I keep myself in good shape for my age so I didn't have a gut and even a few abb muscles on display (a four pack maybe), so I guess I looked ok shirtless in only a pair of mid thigh red swim trunks. Flakes of old paint stuck to my sweaty skin.

I was working on the side of the boat that was opposite the girls. With the boat between myself and them. I was lost in the repetitive work and music when I noticed someone approaching me.

Of course it was Jenny. She had her eyes locked on me and, without trying, her body swayed sexily as she came towards me.

"Jenny," I said, raising my hand to try and signal her to stop. She didn't even slow.

She came to stand directly in front of me and then dropped to her knees.

"Kristen is asleep," she said. "She'll stay that way unless you wake her up. You don't want her to wake up do you?"

I really did not.

For one, I had no idea how I would be able to explain away my sister in law kneeling before me. For another, she had already pulled her bikini top aside and set free her perfect breasts. I wanted nothing to interrupt that view.

As I looked down at her, dumbfounded she reached forward and in one move yanked my swim trunks down and my cock, which had already started to harden as soon as she was walking towards me sprang free.

I was not a porn star but I had a decent cock, I figured. It was about 7 and a half inches long and pretty thick. I was uncircumcised so the purple head hair peeled out from its sheath of skin sunlight catching the small amount of pre-cum that was forming on the tip. I did not shave but I kept my pubic hair trim so my cock was not half buried in a thatch of hair.

"Oh fuck this is nice," Jenny said quietly and gripped my cock, it filling her small hand. It was soft and I groaned with pleasure as she began to pump it.

"Oh fuck, it's just as nice as I remembered," she said quietly. "Does Kristen love this cock like I do?"

I didn't have an answer for that. She didn't seem to need one. She shuffled, straightening her legs to be higher and placed my cock between her breasts. She must have just applied lotion because as she pushed her beautiful globes together and began to slide me between them I moved easily, the only friction being pleasurable.

"Does Kristen do this for you, daddy?" She asked, making eye contact as she used her tits to fuck me. "Does she let you fuck her tits like this?"

"No," I said quietly. I was thrusting now, unable to help myself. The feeling of sliding between her melons was too much to hold back. My hands, shaky at first then determined, lifted and gripped her breasts on either side, squeezing them tighter around my rod.

Despite having seen them daily via messages, this was the first time I had touched them since that day in the car. The skin was smooth and firm, her 19 years had done nothing to make them sag. She giggled and removed her hands, letting me take over the fucking.

She reached between her legs and slid one hand under her bikini bottom and I could see that she was rubbing her clit.

Each time I thrust the purple head of my cock would be exposed, foreskin pulled back. She angled her head so that she could lick the tip each time it emerged from her cleavage.

"I want to do anything she doesn't do for you daddy," she almost whined. "I'm yours. I'm your slut, aren't I? Tell your princess I'm your slut."

"Oh fuck," I grunted, lost in the feeling. "You are. You are my slut."

"Call me Princess."

"You are my princess slut."

She moaned at that and then leaned back, my cock sliding free of her magnificent tits. I grunted again, this time with frustration but it was short lived.