The house was buzzing with last minute activity as Adam, his sister Amber, and their parents were packing the last bit of things for university. This was Amber's first year and Adam was a second year. The family had rented a small trailer to pack their stuff in, but it still wasn't enough space so they utilized most of the space inside the SUV.
Loading up in the stuffed vehicle, Adam and Amber realized the only seating option was for Amber to sit in Adam's lap. Dad turned on the radio to the local news and talk channel. He was a bit hard of hearing from his time in the military so he always had the volume up loud (this will become relevant). The vehicle pulled out of the driveway with a bump from the street gutter transition to the roadway. This caused Amber to bounce up and slam back down onto Adam's lap causing a bit of quick discomfort for him.
Adam let out a grunt, "Oh, I'm sorry bro." Amber said as she adjusted herself for their comfort. This was going to be a long ride and Adam was already dreading it. The brother and sister popped in their earbuds and got settled in.
Adam was going through a punk phase so he started a classic punk station on the Musify app. He reclined the seat as much as possible due to how stuffed the vehicle was, it wasn't much.
Amber had just started listening to a very erotic audiobook called "Forbidden Pleasure". She opened the audiobook app on her phone and hit play. The narrator started reading "Her fingers traced the intricate patterns on the antique lampshade, casting dancing shadows on the walls of the dimly lit room. The soft, rhythmic ticking of the grandfather clock provided a soothing backdrop to the tension that simmered between them. His gaze, dark and intense, held her captive, promising a forbidden pleasure that she both craved and feared."
A little time had passed when Amber realized why the book was called "Forbidden Pleasure" the narrator continued, "The crackling fire cast dancing shadows on Henry and Victoria's faces as they sat huddled together on the worn leather couch. A comfortable silence had settled between the brother and sister, broken only by the occasional soft creak of the old house. Their eyes met, a spark igniting between them that was both forbidden and exhilarating. As their hands brushed against each other, a shiver ran down their spines, a testament to the secret desire that had been simmering beneath the surface for far too long."
Amber, forgetting for a moment where she was shifted a bit and allowing her fingers to drift to her pussy. She found herself already wet, feeling the dampness on her panties. She also now noticed that Adam's cock was laying along the crack of her ass. Soft, but yet still large at the same time. This and the erotic story she was listening to sent a musing through her mind. "What if...I wonder what Adam is like in bed?"
This was not a thought that was foreign to her. Since he left for university last year she often had thoughts like this but never acted on it. The most she had done was secretly name one her teddy bears "Adam" and on occasion would sneak her mom's dildo when she was away and ride the dildo and "Adam" teddy bear.
Out of self gratification knowing Adam would be checking her out and for Adam's amusement she Amber would walk around the house in just a tee shirt and panties when he was home. When their parents weren't home she would put on the skimpiest bikini, one that barely covered anything and left really on the color of her nipples and pussy lips to the imagination.
Oftentimes just a quick walk past Adam's room, noticing him watching her walk past would turn on the floodgates. By the time she got back to her room to make herself cum, her pussy would be dripping her musky nectar.
Amber shifted again feeling Adam's cock roll and adjusted against her slightly spreading ass cheeks. Amber heard a slight grunt from Adam, only this time it was different, it was more breathy and moany. She could feel a slight thickening and stiffness growing between her cheeks.
Adam could feel his cock was laying perfectly between his sister's delightfully plump ass cheeks. With every move and adjustment either of them made, caused him to concentrate even more about not getting an erection.The thought of doing his sister had entered his mind from time to time, but as hard as he tried to suppress the thoughts they were popping in with increasing frequency.
Amber looked amazing, especially now. She was a bit of a late bloomer. When Adam had gone off to university last year she was just his little sister starting her senior year in high school. Through the year he noticed that she was really starting to develop into a woman...no, a hot woman in his eyes.
He thought about how her ass plumped up and took on a great definition. Her tits, wow had they transformed. They were now at least as large as their mom's. He always just assumed his mom's tits were large because she had given birth to him and his sister. But that was not the case with Amber, and to his knowledge she has never been pregnant.
It was a difficult summer this year at home. The family has a pool, and Amber loves to swim. She was also quite proud of her body and loves to wear bikinis, some a lot more revealing than others. He noticed that Amber only wore the most revealing ones when their parents weren't home. He could help but notice she often only wore a tee shirt and panties when lounging around the house. Many times her shirt would be short enough that her panty clad pussy mound would be on display below the hem of the shirt.
One that he loved to see her wear was a t-back thong and matching top. The part that covered her pussy, did just barely do its job. The thong was just a string that was swallowed up by her voluptuous ass. The top wasn't much bigger, if it shifted just a millimeter, her areolas would make themselves known.
He can't count the times over this summer he masterbated to the thought of seeing his sister naked. Knowing that they were going to be living together at the bungalow was driving him insane. Perhaps he would see her walk from the bathroom to her room naked thinking he wasn't home.
It had been about an hour when Amber leaned forward to talk to her dad about needing a pit stop to stretch her legs and use the restroom. When leaning forward she glanced down and could see the outline of Adam's balls through the thin material of his running shorts. It was all she could to not reach out and cup them.
Even though they have lived together their whole life she has never seen Adam naked. The most that has been seen is his silhouette in the shower if she had to pop in to get something while he was showering. From what she has seen though, Adam is certainly working with a sizable member.
Amber leaned back onto Adam's chest, she tapped him on the inner thigh which made him jump a little with surprise. When he removed an earbud Amber whispered to him "Hey, bro don't worry, I don't mind, but I can see the outline of your balls through your shorts."
Adam shifted and cleared his throat. Amber lifted herself slightly as he shifted causing his stiffening cock to slide further between her ass cheeks. When she lowered her full weight back down onto Adams lap, she could feel the dampness from her pussy was migrating down towards her taint. She could also feel Adam's cock was slowly growing and through the thin material of both of their shorts she could feel the heat of the blood surging into his member.
Adam announced "Hey Mom, Dad... I um need a... uhh..to go to the bathroom and get another water." Dad said "Yep, we got an exit up here in about a mile with a Pump It Up convenience fuel store."
Amber, still leaning back, continued her whispering "What's wrong bro, you feeling something kind of strange?" "Well...I can feel my penis is getting hard and feels like a hotdog between your buns...so yeah...and then you mention that you can see the outline of my balls." whispered Adam.
Amber looked towards the front of the car to ensure mom and dad were not looking before she reached down and softly cupped Adam's balls. "You mean these balls right here." They seemed even bigger in her hand than she ever imagined. "And this hotdog you speak of...it's more like a thick sausage. Your cock (emphasizing cock) feels like it's snuggled in nice where it's at."
Still at a whisper "Amber, what the fuck dude? You're grabbing my balls."
"Why yes I am good Sir." Amber said cheekily "And might I add they are a mighty fair pair if I do say so."
As they merged onto exit the vehicle and trailer got into a slight rhythmic bounce with the pavement. This caused Amber to move up and down slightly on Adam's lap. At the lowest apex of her bounce Amber could feel her juices escaping more and more. Luckily both siblings were wearing black shorts so any dampness from her would be easily camouflaged.
Both could feel Adam's cock get instantly hard still sandwiched in Amber's ass.
As they were getting out of the vehicle at the fuel store Amber whispered "I know you're hard now and probably ready to explode but you better not go in there and rub one out."
