Note: This story was dynamically reformatted for online reading convenience. On the way home (Incest bro-sis ped) "Can you just sit still without jumping if you are going to sit on my lap for few hours, Di" I yelled at my little sister Diana. She just turned her head, stuck her tongue and made a nasty face to aggravate me even more. I knew that I was stuck with her for several hours in the back of a tow-truck. Our road trip to the northern beaches of California ended in a disaster when my Dad's newly restored 1964 Studebaker broke down on highway 101 and had to be towed all the way to Sandy, Oregon. Luckily for us, Uncle Bob runs an auto repair shop 50 miles from where the car broke down and he came and rescued us, by loading the Studebaker on his tow truck, driving us with it home. The only problem was having two toddler cousins that we had to take along with us since Uncle Bob has been a single parent ever since Aunt Rita passed away last year. With his kid's car seats in the back of the tow truck, Di and I had very little room and therefore she opted to sit on my lap for the ride home, while my parents and Uncle Bob, who drove the truck, occupied the front seat. We kept crawling behind lumber hauling trucks on HWY 101 when the sun was beginning to set. Both our cousins fell asleep around 9 pm and I tried to be as comfortable as I could be with a 14-year-old sister on my lap, who tried restlessly to get herself settled to take a nap herself. Di and I didn't have much in common, since four years separated us. We didn't have common friends or play together or anything. Sometimes we watched the same programs on TV. But I loved her as any brother loves his sister and protected her when necessary. She is a 'woman waiting to be born' our mother always said, and I think that was true. She was blessed with a very attractive face, but as with many teenagers her age, she was still trying to shake some of her baby fat off her body before she'd become truly stunning. In my case, I always liked girls with large buttocks and rounded legs, so I always thought Di was not, except for her still developing breasts. As it began to get darker, we navigated through the mountainous roads heading home. Mom dozed off on Dad's shoulder and Di leaned against me and tried to doze off herself. Suddenly, Uncle Bob took a sharp turn making Di lose her balance. She quickly tucked her shins under my legs to stay in balance. "Are you cold?" she asked, grabbing a beach towel from the bag on the floor and covering her exposed legs. "Not really?" I answered, as I was being heated by her buttocks resting on my lap. Di reached behind and grabbed my left arm and brought it around her front, just below her breasts and rested her head again on my shoulder. I put my right hand on her thigh, over the towel. We didn't say anything. The ride in the tow-truck wasn't comfortable as I started feeling every imperfection of the road as we rode. To make things worse, every bump we hit made the truck move several times as the weight of the Studebaker that was in the back kept moving about. To add to this difficulty, I started feeling the back of Di's bare legs on my thighs as the dress she wore had ridden up due to the movement. It was causing an unintended, but decidedly pleasant, sensation on my cock. Not being with my girlfriend for nearly ten days may have been a factor as well. I tried to close my eyes and focus on other things to forget the feelings between my legs. I found it difficult when she slid down a bit further causing my right hand to slide up near her right breast. I looked out of the window, seeing nothing but darkness. I tried to think about other things again, but my cock kept on adding length involuntarily. I didn't want Di to feel it or wakeup and find that I was having a hard-on. This was the first time ever that I wished I had a smaller member, but I am big and I am proud of my thick eight-inch cock. 'How can a guy not get a hard-on when a girl with a silky-smooth butt is sitting on his lap and her pussy is putting out so much heat?' I tried to reason with myself. Then I thought the best remedy might just be to relieve the tension building up in my balls. I knew that once relieved of its boiling load, my cock would settle down, hopefully for the duration of the ride. But I wanted to make sure that I didn't do anything drastic or wake my sister up. I slowly slid my hand under the towel in search of my cock, but found it difficult to reach between her thighs. I decided to leave my hand on her leg until an opportunity came to reach further to grab my cock. Di appeared to be fast sleep on my shoulder, since she did not move. I felt the softness of her thigh where my hand rested and proceeded to slowly reach down again towards my pulsing member. I was afraid of forcing my hand between her thighs, since she might wake-up and then how would I feel? However, I was encouraged by her non-reaction to having my hand on her thigh. I began to slowly caress her and move upwards towards her pussy. Then without thinking twice, I brought my left hand around her body and placed it over her other thigh and made both of them both wander up and down together everso slowly, caressing her legs and moving in between them to break loose my cock. I felt the heat coming from between her thighs. At that moment, I wanted so desperately to run my hands down her smooth legs, to feel the heat that was generated between her flawless thighs, but I refrained. My cock was as hard as it has never been. Even though I wasn't doing much, just the thought of fondling my sister's naked thighs had got me very excited. I kept caressing her inner thighs while massaging my cock between them with the other hand. I knew she was fast sleep by the way she was breathing close to my ear, so I continued with my daring action while our parents were only a few feet in front of us. Not wanting to wait to any longer to release my load, I pulled my stomach muscles in and pushed down the elastic band of my shorts. I slid my hand in and slowly brought my thick cock out to breathe aroma of the warm air between her thighs. My cock angled to the left, resting on her soft inner thigh. I waited for a second before placing my hand on the head and slowly massaging it. Then I found it more pleasurable to rub my cock on her thigh than to massage my cock-head. As I continued to rub my cock on her smooth skin, pre-cum that oozed off it made it slippery and gave me a much more pleasurable sensation. What happened next almost scared the hell out of me. When Uncle Bob took another sharp turn, Di brought her knees together and leaned on my neck to balance herself, sandwiching my hard cock between her inner thighs. I thought that I had got caught with my hands in the cookie jar. I even wondered whether our parents were looking in our direction. However, as luck would have it, she went right back to sleep, but didn't part her knees. Not wanting to cause further panic, I rested, but soon found that having my cock between her smooth thighs was a wonderful experience. As the tow truck continued to vibrate, Di's hips moved rhythmically, making my cock ride in between them. By then, her thighs were covered with my pre-cum. This made it so pleasurable that I simply placed my hand over the cock-head and massaged it gently. I had thought it felt good before, but I could hardly believe how great it felt now. I suddenly felt Di's hips jerked forward along my erection. Then instantly I felt her thighs tightening around my cock as we rocked with every jerking movement of the tow-truck. The heat I felt racing through my cock seemed to double as she firmly held it between her soft thighs, now very slippery and wet with my pre-cum oozing between them. I placed my hands on her knees and slowly started to thrust my cock between her soft and creamy flesh. I felt the pleasure climb higher and higher with every passing moment, bringing me closer and closer to orgasm. I became bold and wrapped my arms around her body. I stroked my hands along her belly, moving up until I held both of her small tits over the dress, cupping them in my palms. I knew she was still fast sleep by her breathing pattern. Feeling her small nipples sent a fabulous sensation down between my legs, causing my juices to boil in my balls, knowing that I was playing with my sister's sacred parts. I rubbed and squeezed them softly. I felt my balls begin to tighten and I knew I was going to blow my load. I quickly covered the head of my cock to ensure that no cum would fly above it. The bursts of hot sticky semen blasted into my hand and slowly dripped down her thighs. I waited for few seconds to regain my composure then I quickly cleaned my juices off of her thighs with the towel and pulled my pants up. "We will make a gas stop in few minutes," Uncle Bob suddenly announced. I closed my eyes and acted as if I was fast sleep. see part 2