When I woke up the next morning I had a hard time determining whether all of last night had just been a dream. It was a strange sensation, I almost wanted to pinch myself but I knew that I was currently awake. What I needed was someone to go back to the night before and pinch me. But it was too late for now. As things became clearer I realized I was lying totally naked in my sister's bed, and with this realization I excitedly realized that last night was real and that Brittany and I had actually made love to each other.The next realization I had was that Brittany was no longer in the bed with me. I had a quick fleeting worry that she had freaked out about what had happened and had bolted from the house in horror at what we had done. As that thought was spinning its way around my brain I heard the tell tale sign of the shower being switched off and the loud noise of the bath running and then shutting off all together. So Britt was in the shower...I rolled over in bed, rubbing my eyes to clear things up a little more for me. I was now on my back at the edge of the bed. A moment or so later I heard the bathroom door open and heard Britt returning. She walked into the room in her towel only."Hey good morning sunshine!" she yelled my way. "I felt gross this morning when I woke up, who knew sex would need so much clean up!" As she finished that sentence she casually dropped her towel, unveiling her stunning naked body once again, this time in broad daylight and five feet from my wide eyes."Yeah...yeah you're right," I stammered. She was now brushing her hair. I didn't realize that my cock had slid out from under the blankets and was now absolutely rock hard looking at my sister's beautiful naked body."Hmm, well looks like someone's ready to go again," Britt said, walking to me and grabbing my cock with her off hand and beginning to stroke it up and down."Oh...uh, yeah I'm definitely ready if you are," I said, almost immediately regretting being so forward.Britt stood up and walked to the dresser. "Hmm, we'll see. I don't know if you have been good enough to deserve it again" she said playfully. My heart was pounding thinking how lucky I would be if this actually happened again. I guess in my wildest fantasies I never actually thought that...THIS would become a thing.Brittany made her way back over to me, her hips swaying and her perfect boobs jiggling ever so slightly as she walked. I began to sit up to kiss her but she pushed me back down on the bed. "Shhh, I've always heard of this and wanted to try it..."With that she moved down and took my dick in her little hand. She gave it a funny look like she was inspecting the whole thing close up for the first time. She then ignited my world by taking the head of my cock in her mouth. Now as a 15 year old I had had close to 500,000 fantasies about girls sucking my cock. But I was not prepared for this. I remember her mouth being much warmer than I had ever fantasized about, and the tightness and surrounding goodness that I felt was amazing."Holy...shit." I sputtered out as I grabbed the sheets and felt her begin to inch her mouth down farther and farther on my cock. I exhaled as my dick reached its deepest point, all but an inch or so exploring the back of her mouth and throat. She began bobbing her head, her hair bouncing as she began to rhythmically suck on my dick while using her right hand to keep stroking the base.The room was silent except for the occasional sucking sounds coming from her mouth. I could already feel the cum building inside me. She began to speed up and every so often would look up at me, her beautiful eyes catching mine and though she couldn't actually smile, I could see the devilish grin in her eyes alone.Luckily I lasted a few minutes longer than I did when we made love the night before. I got bold at some point and even put my hand on her head to guide her mouth as far down on my cock as she could get it. I could feel the cum rising inside me. I was unsure what to do. "Britt," I whispered, "I'm...gonna cum...soon."Brittany looked up at me and just nodded. It was such a beautiful look. I could feel the cum building now, ready to explode. "Britt...now!" She nodded again but didn't move from my cock. I exploded into her mouth, cumming one spurt after the next, my beautiful sister swallowing load after load. Finally she lifted her head off of me, keeping a hand on my still hard dick. She spit out the last shot of cum I had shot into her mouth."Ughh gross! I...definitely thought that was going to be easier to swallow but that's nasty! Noelle said she swallows and it's no big deal, the bitch." She picked a tshirt off the floor and and wiped around her mouth with it. "Fuck, now I'm going to need another shower!"I wasn't done with her, though. I got up and flipped my sister on her back, playfully jumping onto her. "Wait a minute," I said, "you're not getting out of here that easily!" i positioned my legs just under her butt on the bed and I began kissing her belly and grabbing at her boobs with my hands. I lightly kissed down her flat lower belly, her beginning to breath hard already.She let her legs fall away, totally relaxed as I kissed her inner thighs. I remember trying to be as smooth and slow as possible even though I was dying to dive right into her pussy. I made my way down to her pussy, which was already glistening and wet. I could faintly smell a sweet essence coming from her. I slowly began licking her clit, going in circles like I had probably learned to do from some online forum.Her heavy breathing started to pick up as I hit her clit. I realized that she was much MUCH wetter than I had anticipated. I reached behind her legs and pulled her closer to me as my tongue circled her clit, a little bit faster now. I reached my right hand down and slowly pushed a finger into her vagina...even one finger was tight. She moaned as I pushed inside of her. I slowly moved my finger in and out while licking faster and faster, occasionally sucking on her clit in between licking it with my clit.I glanced up to see Britt writhing around, absent-mindedly playing with her boobs and with her eyes closed. I pressed my tongue in deeper, rubbing her clit firmly with it as I was now licking as fast as I possibly could. I continued pumping one finger inside of her as I heard her begin to actually moan outloud ever so slightly.She lifted her hips up off of the bed, pushing my mouth onto her clit. I got a whole mouthful of her wetness at this point and reveled in the taste. She had this very sweet slightly musky taste that was simply delicious. She screamed out as I felt her pussy tighten around my finger, pulling it in as she gushed cum over it. She laid back down, her breathing slowing as I lifted my head out from between her legs. She was still rubbing her tits slowly but firmly as things settled down.I laid along side her, taking a deep breath and letting my hand fall on her leg. I noticed my cock was again rock hard, turned on by what has just happened. "Oh no buddy," she said, "I'm not done with you yet."After catching her breath she leaped up and straddled me. One of the hottest sights I've ever seen in my life ensued. I looked down to see her sitting on me, her thin waist and flat belly contrasted by the sides of her round ass being pushed out to the sides by my legs. I could just barely see the front of her pussy rubbing against my cock which was bent all the way back towards me. Her arms were bent someone inward, pushing her breasts together making them look bigger, puffier, and perkier than usual (which says a lot). She smiled as she bent forward, reached behind herself to grab my dick, and positioned it at the entrance to her vagina.She lifted her ass up and slowly lowered her soaking pussy on top of me. In contrast to the night before where we had to go so sloooowly to get it in, this time she took it in one smooth motion. It blew my mind how tight she was even with how insanely soaking wet she was. I felt her pussy grab hold of my dick and her ass hit my legs as she took my whole dick inside of her. She leaned forward and kissed me as she began to grind her hips to ride my cock.I felt her breasts rub over my chest, her breathing again picking up as she kissed me. The speed at which she was taking me slowly but surely picked up. My cock was rock hard and I was in heaven, but thanks to the blow job earlier I could tell I'd last longer than the night before. She continued kissing me but at a certain point at the angle she was at she could only ride me so fast and so hard. Once she realized this she leaned back, now riding me cow-girl style, with her totally vertical while I was lying down.Her body was something to behold. In terms of girls who you could have your first sexual experience with, I firmly believe that I had the best. I watched as she bounced up and down on my dick, her boobs just barely bouncing as they were so firm and round. Her flat belly and perfectly shaped hips just oozing the essence of a woman and her warm tight pussy hugging my cock. It was all too much. The sex this time was different too. Last night we were two kids fucking around and trying this whole sex thing for the first time. Today we were lovers, two people having sex with each other...a....couple, just doing what we wanted to do together and feeling it all together.She rode me this way for 10-15 minutes, occasionally leaning down and supporting herself on my chest while she bounced on my cock. I would occasionally reach up and play with her tits...squeezing her nipples and feeling them harden between my fingers. I even reached up and touched her face, her spontaneously taking a finger in her mouth and sucking on it.I also heard her talk dirty for the first time, saying several things like "Oh fuck Sam I love your cock inside me," or "Ohh yes fuck! Fuck me Sam, fuck me!" It was incredibly hot. I saw in her in a totally different light that day. Eventually she was ready to cum and so was I. She was bouncing up and down on me as fast as she could, now almost screaming as she let loose, clamped down and came on my dick. I moaned out as I released inside of her, cumming for the 3rd time in twelve hours and for the second time deep in my sister's pussy.We collapsed on the bed, speechless. We fell asleep in each other's arms and took a short nap. When I woke up, my mind went into a whirlwind. Was this going to continue to happen? Where do we go from here now that we've "gone all the way?" Are we like...a couple? Or just fuck buddies?I thought I was the first one awake but apparently Brittany was already awake."If we're going to keep doing this, I need to get on birth control like, ASAP," Britt said, half laughing. "You can't just keep cumming in me like that." "Oh and I'm not just a sex doll you know, you need to treat me like a lady and take me out too." She got up and walked out of the room to take her second shower before noon that day.Well, I guess she answered my question about whether or not this would happen again!