Last summer, I traveled cross-country in a van with my eighteen-year-old girlfriend, Jessica, and her sixteen-year-old sister, Penny. As the trip progressed, I began to notice Penny's cute sexy, young body and she in turn became more and friendly towards me. It was a bit embarrassing actually. A number of times Jessica almost caught me staring at Penny's hot, sexy little ass when she bent over in those TIGHT shorts and thin T-shirts she always wore. Not that Jessica is all that plain mind you. Both girls are extremely sexy, and despite the fact that they were sisters, (or maybe because of it), I kept fantasizing about a threesome.

One evening, as we relaxed with a few beers on the mattress in the back of the van, Jessica asked me if I thought Penny had a cute body. Shit! In my book, Penny had the kind of nubile young teenage body most men only dream of getting close to. But I was determined to be diplomatic and not get myself into trouble with Jessica.

"Sure!", I grinned. "I guess she's not bad... for a kid!"

That remark got a giggle from my girlfriend and a thump in the ribs from Penny. Still playing the diplomat, I kept telling them how gorgeous and sexy they both looked. We were all a little tipsy from the beer by then and snuggled up together. Penny gave Jessica a little conspiratorial smile and cuddled up closer, running her fingers tantalizingly up along my inner thigh and pressing her firm young tits into my shoulder.

I looked at Jessica, worried that she'd get jealous of her little sister being so intimate with me but she was smiling too. Then, she said something that really threw me.

"Penny and I share most things, David... including boyfriends. Does that bother you?"

I glanced at Penny who just rubbed her hot little body up against me and gave me a cheeky grin.

"Um... er... no!", I stammered, reaching tentatively out to stroke one of Penny's hard young tits through her T-shirt "Jeez, I don't mind if it's okay with you, babe."

"Great!" giggled Jessica. "Why don't you start by making love to Penny while I watch!"

I was totally amazed by my girlfriend's shameless suggestion, but Penny's hot little hand on my hardening cock told me that I had not been hearing things. Jessica was dead serious... and so was Penny.

As Jessica lay back and watched, Penny grabbed my hand and put it up under her T-shirt. Her small breasts were firm and pointed and her nipples stiffened immediately at my touch. Jessica made herself comfortable while Penny stripped off her T-shirt, revealing the most gorgeous set of young tits I'd ever seen. They were much smaller than Jessica's and sort of cone-shaped with pert, up-tilted nipples that just begged to be sucked.

"Oohh, Davey!", she moaned, rubbing a hand between her legs suggestively. "I'm so hot! I want you to fuck me so much!"

Jesus! That was all the prompting I needed. Moving toward her eagerly, I fondled Penny's tits as she tugged down my shorts and freed my rock-hard cock. Her gentle fingers stroked my stiffness and played with my balls. As the heat in the van started to build, I worked my hands down to her shorts, unzipped them, and eased them off her long, slender legs. Her tight little cotton panties followed.

When I reached for her cunt, I could feel that Penny was exceptionally hot and wet down there. I wanted so much to lick her tasty little slit, but I thought that Jessica might get jealous, since she enjoys the way my tongue turns her on. As if she read my mind, Jessica said, "Go for it, David! Suck her pussy. Just save some for me, okay?"

With groan of pure lust, I spread Penny's creamy young thighs, pushed my tongue deep into her lightly-haired little pussy and began to lick at her open sex hungrily. Her teenage slit was smaller and tighter than Jessica's, but just like her older sister, the more I sucked Penny's sweet little pussy, the more her fuck-juice flowed, spilling out over my probing tongue like a fountain. I licked her cunt-cream up as fast as I could, but some managed to escape, trickling down between her thighs to pool in the dimple of her upthrust little asshole. I found her tiny clitoris and began to make slow circles around it. Penny's reaction was immediate.

She grabbed my head and pushed my face into her crotch real hard, at the same time grinding her sweet little sixteen-year-old cunt up against my mouth. Her legs were spread real wide so that her prominent young pussy-mound was spread out before me like jelly on a plate. I licked and sucked and probed Penny's tasty little fuckhole until she was frantic with pleasure.

Her constant whimpering moans and rapid breathing told me she was on the verge of a climax. Then, suddenly, her naked young body tensed and shook. She held my head tightly against her cunt, let out a sharp cry, and arched her back, shuddering wildly as I sucked her pulsating little clit like crazy.

With a sigh of total satisfaction, Penny collapsed her ass back on the mattress and just lay there with her eyes closed, moaning softly. I looked over at my girlfriend and saw the lust in her eyes, it was obvious that watching me eat out her little sister's cunt had gotten her REAL horny. She had one hand inside her panties and the other up under her blouse, rubbing herself shamelessly. Her eyes were on my big, throbbing erection.

"God, Dave, that was so hot!", she smiled. "I loved watching you suck Penny's pussy. But right now I need that big hard cock!"

She pulled off her jeans and panties, then got onto all fours, leaving her furry, blonde pussy wide open to me from behind. She lowered her shoulders and raised her ass, reaching back to grab my cock. Once she had it in her hot little hand, Jessica positioned the tip into her slit and wiggled backwards onto it.