Tim and Ashley helped their mom and dad unpack the station wagon and stow everything in their vacation cabin in Montana.
They had all the canned food and wood and supplies they would need for a two month stay, even though they would only be staying for a week's vacation.
Their parents left to make the hundred and twenty mile drive into the nearest town for "just a few more things" saying that they would be back before nightfall.
Tim and Ashley didn't mind. They were both thirteen and felt old enough to handle things themselves. They had always gotten along together because of the fact that they were fraternal twins and shared the same facial features as well as the same red hair. They had always looked so identical. That is until this past year when first Ashley had gotten taller than her brother and started to develop definite female attributes like small, noticeable breasts and a filling out of her thighs and hips and bottom.
This year Tim grew to match and then pass his sister in height and his voice began to deepen and he became wider through the shoulders and more muscular.
These changes were only noticed in passing and the twins continued to be occupied with school and friends and video games and TV and movies.
This week was a chance for the family to be together and they all looked forward to it.
Tim and his sister set up their small room in the cabin. As always, when they stayed here, there was only one bed and they had to share it. They didn't mind the once-a-year inconvenience. They had spent many a night, during past vacations, talking in the dim light about school and friends and what they wanted to be when fully adult.
Tim got his fishing gear and went to the crystal clear lake while his sister put on her two-piece suit and got some sun out on the deck. Tim caught two large fish and brought them up to the cabin and cleaned them and thought how good a fisherman he had become.
As dinnertime came, their parents did not and, though mildly worried, both the kids went about making dinner, cooking the fresh fish and frying a couple of cans of potatoes.
Just before dark a car pulled up and Tim and Ashley ran outside expecting their parents but seeing that it was Mr. Canfield from a nearby ranch.
"Got a call from your folks, kids," he told them. "They got car trouble and will get it repaired and be here with you in a few days."
"Thanks, for coming and telling us," Tim told the old man.
"No trouble. You kids be good."
Ashley smiled at him. "We will."
After Mr. Canfield left, Ashley and her brother felt tired and readied for bed.
Tim stripped down to his jockey shorts and got into the big bed as he watched his sister remove her top, bra and shorts and then pull her long pink t-shirt (which she always slept in) over her head. Tim could really detect the curves of her young body as she tugged the shirt down to her thighs. He didn't expect it, but the sight caused a stirring in his loins.
Ashley then got into bed beside him and it was quiet for a time.
"Do you think mom and dad are okay?" Ashley finally asked her brother.
"Sure, sis. You KNOW they can take care of themselves."
"Yeah," she said and then it was quiet for a while longer with little sound in the room..
It was Ashley's voice that broke the silence. "Tim?"
"Do you think I'm.... pretty?"
"Why do you ask?"
"I saw you... looking at me as I got ready for bed."
"Oh... sorry about that. I didn't mean to stare. It's just that you ARE pretty Ash and I noticed it and..."
"It caused something to happen."
"I got... stiff."
"You know. My... my penis got hard."
"Really?" Ashley said, sitting up slightly and looking at her brother beside her. "Can I... see?"
"Gosh, Ash. That's a lot to ask a guy. Especially your own brother."
"Whose else can I see?"
"I don't know."
"I have to see one some time."
Tim felt embarrassed and awkward but he also felt horny and curious himself so he pulled the covers down and then pulled down his shorts as his sister, wide-eyed and pretty, watched him.
"Gosh," she exclaimed as it came rigidly into view and popped up from her brother's red-hair covered balls. "It's so BIG! Do you think it would be okay if I... touched it?"
"Uh... yeah. I guess that would be okay."
Ashley reached timidly to her brother's organ and first touched it with her fingertips and found it to be fleshy and warm and very hard. Then she wrapped her hand around as much of it as she could and held it.
"Oooh," she said. "It feels so nice. Holding it is making me feel light-headed and breathless and is causing tingles in my breasts and between my thighs."
"Yeah. Like there's something that we are supposed to do... or NOT supposed to do. I can't figure which but I sure want to do... something."
"Hmmm," Tim said as his sister started to rub his shaft up and down slowly, making his penis ooze a slick liquid drop from its tip as he looked at her body beside him.
"Sis, may I touch YOU as you touch me."
Ashley seemed to think this over for a time and then said, "Okay," as she let go of her brother and then reached down and removed her panties and pulled them off.
Tim could now see his sister's pretty pussy, covered with the same down of hair as his own sexual organs. In the dim light he could even see the pink flesh between the pillow-like lips of her pussy.
Almost holding his breath, Tim reached for and cupped his hand over the heat and sublime softness of Ashley's sex. It felt wonderful and made his cock, for some reason, go even harder.
"Put your hand back on me," he instructed as his fingers found her slit and began to gently explore her there.
"That feels so GOOD," Ashley said as she wrapped her brother's shaft in her hand again and began to stroke it slowly.
Both siblings explored each other for a time before Ashley asked, "Shouldn't we be doing more?"
"Well... in the movies... people kiss."
"Will you kiss me while we do this?"
Tim shrugged. "Sure."
Rolling on his side to her but not taking his hand from her wet pussy, Tim softly pressed his parted lips to his sisters mouth and their faces pressed together and their tongues met and their hand and finger movements became faster as their breathing became more rapid and then Ashley pulled her bleary face back and said, "Something's going to happen to me, Tim. Don't stop what you're doing and kiss me."
Tim kept working his fingers against the wet folds in the notch of his sister's pussy as he kissed her harder and felt her sucking at his mouth as her legs stiffened beside him and her hand worked faster as his burning penis and, just as she caught her breath and sucked even harder at his mouth, Ashley went totally rigid in orgasm as Tim lost all control and started to ejaculate long streams of thick cum all over his sister's exposed loins and flat, rigid stomach.
They both seemed to cum for long, breathless moments before their orgasms let go and they broke their forbidden kiss and just cuddled beside each other, panting in the near darkness.
"That was fantastic," Ashley said, breathlessly. "I never knew it could feel that good."
"I will admit that I have done it to myself and it felt good," Ashley stated. "But not as good as when you did it to me while I did it to you."
"What can we do next?"
Tim thought about it as he looked into his sister's pretty, green eyes. "We have another few nights together here. I'll tell you at bedtime tomorrow night."