Helping My Girlfriend's Sister

It was a relief to finally check into the hotel after our road trip down to Atlanta. I was psyched for the weekend - A friend was getting married, and the trip to Atlanta was doubling as a vacation for me and my girlfriend, Kate. Oh, and my girlfriend's sister, Gabrielle, who had just graduated from high school and was tagging along since she had nothing better to do. Don't get me wrong, I'm definitely not complaining about spending a weekend with two beautiful girls. I was just worried about having our extra-curricular activities curtailed by the presence of my girlfriend's sister, a very impressionable and innocent girl who spent her entire high school career with her head buried in books.

After checking in and tossing the bags on the beds, it was time to explore the city. We spent the rest of the afternoon in Piedmont Park on rented bikes, had dinner at a nice restaurant nearby, and returned to the hotel to unpack and relax before the wedding the next day. As I was unpacking our bag, I realized Kate had also tossed in a few bottles of wine - Great idea, since we couldn't get Gabrielle into any of the bars nearby! The three of us drank our way through one of the bottles while watching a movie, and it didn't take long for us to realize how late it was.

Gabrielle got up from her bed, a little wobbly from the wine, and headed to the bathroom to change. As soon as the door was closed, Kate was on top of me, her lips mashed against mine, her tongue driving into my mouth, her pussy grinding into my cock through our clothes.

"Kate!" I gasped as we came up for air, "Gabrielle's going to be back any second! Don't start something we can't finish!"

"I'm sorry, babe... But we'll finish it later, I promise," Kate said with a wink as she rolled back onto the bed.

Just then the bathroom door opened and Gabrielle walked out, wearing a tight-fitting camisole and pair of white panties. I knew she was hot, but damn! Her C-cup tits looked absolutely fantastic through the thin material, her large nipples pushing through the fabric. The look on my face must have been obvious, since she quickly said, "You don't mind seeing me like this, do you? I just figured we're all adults, and there's no reason to try and wear clothes we're not comfortable in, right?"

"Um, absolutely... Works for me!" I said as Kate elbowed me in the ribs. If Gabrielle was comfortable enough to be half-naked in front of me, who was I to complain?

"Quit drooling!" she said, laughing.

With that I got up and headed to the bathroom to get ready for bed. By the time I got back into the room wearing just my boxers, both girls were in bed, and Gabrielle was sound asleep, passed out on the bed next to us. "I don't think she's ever had that much to drink before," Kate whispered, adding, "Which will make this a lot easier for us!" She sat up and pulled her tank top over her head, exposing her lacy black bra to me. My cock instantly swelled as I reached for her tits, kissing her firmly on the lips. Kate purred her approval as my hands reached for the clasp of her bra, freeing her tits, her nipples already hard with arousal. I kissed my way down her neck to her chest, cupping one of her tits as I gently licked and sucked on her nipple. "Keep going!" Kate whispered, as I continued kissing my way down her taut stomach. She arched her back, allowing me to slip her thong down her legs, exposing her bald pussy to me, glistening with wetness. Grabbing her tight ass with my hands, I pulled her pussy to my mouth, thrusting my tongue deep into her folds. Kate grabbed my head, grinding my tongue even deeper into her as I licked her to her first orgasm, her body shuddering beneath me.

I looked up into her eyes, both of us panting with desire. "My turn, baby," she said quietly, turning me on my back and pulling off my boxers, freeing my engorged cock already slick with pre-cum. Kate swallowed me whole as her tongue danced across the tip of cock. I grunted my approval, thrusting as deeply as her mouth would take me, knowing I wasn't going to last long. My eyes went wide as Kate kept up her work on my cock, licking it from bottom to top as she gently held my balls.

Just then I happened to glance over at Gabrielle's bed and gasped as I realized she was wide awake and staring at us! My gasp caused Kate to also pause her incredible blowjob as she saw Gabrielle watching us. We both grabbed the covers as Kate exclaimed, "Gabrielle! How long have you been watching us?"

Her face turning red, Gabrielle sheepishly said, "Don't be mad, Katie, but I was only pretending to sleep, hoping you guys would go at it tonight. I've been watching this whole time. I've always heard about the other kids at school having sex, but I've never seen it before!" She paused before continuing, "I don't want to head to college in the fall not knowing what it's all about. Please, Kate, can you keep going?" Gabrielle had tears in her eyes, pleading us to pick up where we had left off. My cock, which deflated as soon as I realized Gabrielle was watching, was quickly returning to its full potential.

Kate looked over at Gabrielle, then back at me. "What do you think, baby?"

"Of course I have selfish motives, Kate, but I don't want your sister going off to the wolves at college without knowing a bit about sex, do you?"

Kate hesitated for a second before responding. "Ok, Gabi, but only on two conditions."

"Anything!" Gabrielle quickly said.

"First, if you whisper a word of this to anyone, I'll never speak to you again."

"Of course I won't!"

Kate then surprised both me and Gabrielle. "Second, if you're really committed to this, you need to be as naked as we are."

I couldn't believe it! Would I really get to see both gorgeous sisters in all their glory? My question was quickly answered as Gabrielle silently peeled off her camisole, revealing two incredibly beautiful tits. Her nipples were a light pink color and hard with anticipation of what she was about to watch. She then stood up, pushing down her white panties to expose her young pussy, wet with arousal, her folds just visible through her dark, trimmed patch of hair.

Kate nodded her approval to her sister before throwing back the covers of the bed to get back to what we started. My cock was aching for some release after two false starts, and was rewarded as Kate swallowed me again. "Damn, Kate!" I gasped as she sucked down my entire cock. I kept my eyes locked firmly on Gabrielle as Kate continued going down on me. I felt the familiar churning in my balls and knew I was close to cumming. Then, out of nowhere, Kate lightly brushed her finger over my asshole, sending me over the edge as I shot load after load of cum down her throat.

"Oh my God, Kate, that was incredible!"

"Kate, that was awesome!" Gabrielle exclaimed. "How were you able to swallow all of him?"

Kate, licking her lips and looking over at her sister, said, "Practice makes perfect, Gabi! Give it time and you'll be giving blowjobs like that too!" She then looked back at me with a wink. "But we're not done tonight, are we babe?"

"Hell no!" I said, as I pushed Kate onto all fours and guided my still-hard cock into her wet and inviting pussy, thrusting into her until my balls were resting against her ass. At this point, Gabrielle was tired of just watching us as she spread her legs open and started playing with her engorged clit. I pulled Kate's head up to mine, kissing her deeply as I continued pounding into. Kate was also furiously rubbing her own clit, just as her sister was doing the same. It didn't take long before both of them came, crying out in unison.

Before Kate even had a chance to catch her breath, I flipped her onto her back and drove into her yet again, her slick pussy drenching my cock with the juice from her last orgasm. Over at the other bed, Gabrielle was breathing heavily and watching us intently. For the second time that night I felt the beginnings of my impending orgasm. Kate felt it too... "Cum into my pussy, baby! Do it!" My balls and cock swelled and I cried out as dumped another huge load of cum into her waiting pussy.

I collapsed onto Kate's chest, spent from having cum twice in the last 30 minutes. All of us took a few minutes to calm down from our heightened arousal. "That was fucking awesome, babe," I said. Looking over at Gabrielle, I asked, "And what about you? What did you think?"

Glancing between me and her sister, her eyes a bit glossed over from having cum, her smooth skin glistening with sweat, Gabrielle said, "I think that was the most incredible thing I've ever seen!"

And even more than before, I was looking forward to the rest of what the weekend held in store...