Jerking off with my friends sister SeXStoRY

So you already know Sam, my friends s****r from the last story where she caught me jerking off and I got to cum on her. Well, about a week later we had another hot run in. This time, when I pulled up to my friends house, I let myself in to find Sam sitting at the kitchen table topless. She was still wearing some green panties, but she was completely naked other than that. I had a feeling she kind of enjoyed watching me cum, although I never expected her to be this brazen, or to try to do something like this. I immediately said, "oh my god, I'm so sorry. I didn't realize you'd be home." She responded very casually, as if it was totally expected for her to be sitting there almost completely naked. "Yeah, I had the day off again today". I responded, "you know your almost naked right?" She replied "of course I do, I just wanted to hang out with you a little more" "What do you mean?" I said. "Well, you got a real good look at me last week, but you were covering yourself up, and shying away. I only think it would be fair if I got to see you too" she said. I agreed to her terms, I was already fully aroused, so I had no problem stripping down for her to see my hard cock again. I was caught off gaurd by this whole thing, but my heart was racing, and my dick was throbbing. I took off my shirt first, and then my pants, and then finally removed my boxers to reveal my fully engorged cock. "Wow, that's a nice cock you've got there" Sam said. "your boobs are pretty nice too" I replied. At this point I noticed something strange on the table, I didn't pay attention to it before because I was too focused on hew amazing naked body, but my eyes eventually found a long cylindrical object that Sam was removing form the table. A dildo, after it disappeared under the table I heard a click and then a buzzing sound. She said "now it's my turn to get off while watching you". I was confused. How did she now I was watching her last time? I asked. "How do you think I knew to come in naked for you, or to be waiting here now?" she asked. I was so turned on at this point I didn't even realize that I had also started stroking my cock to her. She slid back form the table in her chair to reveal fully how she was fucking herself with the vibrating dildo, panties pulled aside. She was breathing more heavily now, and let out some small moans. I started approaching her, cock in hand, jerking away, watching the white dildo sliding in and out of her sweet pussy, occasionally gliding up to massage her clit. As I approached the chair she was sitting in her moans became louder and more frequent. I was now standing right in front of her. My cock inches from her face as my hand stroked back and forth. She let out a loud moan, and then seemed to hold her breath. "Fuck yeah!" she said. Just then, I felt the first burst of cum shoot out of me. It drew a ling clear from her chin, into her open mouth, and onto the top of her head. She continued to scream "OH!". The second burst of cum splattered onto her cheek and dripped down between her tits. I pumped the last few shots onto her tits, because they were so beautiful. I had always dreamed of smothering them in sperm. As the last drops fell from the tip of my cock, and onto her perfect smooth round breasts, her breathing started to slow. "God I love your cum" she said. This was probably once of the hottest things anyone has ever said to me, but all I responded with was, "let me get you a towel". she replied to me "I'm not done yet, I've only cum once". Which in combination to the cum comment kept me fully erect, something that had never happened to me before. I was already walking behind her to grab a towel form the kitchen, when I hear her start moaning again over top of the continual buzz of her white dildo. As I reached out for the towel I realized I had started jerking off again without even noticing. Now I was looking back to her with a towel in one had, and my dick in the other. It felt like I was watching something I wasn't supposed to, like she didn't know I was there, even though she was full on masturbating in that chair with my cum in her hair, face, and tits. As I approached her from behind, I was jerking so fast, and hard. I couldn't stop because all I could do was watch her get off with my cum on her. I couldn't believe this was happening. Once I was about halfway over to her she stood up out of the chair, and put one foot up on the table to I could see the dildo fucking her even from behind. I stood there jerking a watching her fuck herself through her hot green panties. As I walked closer to her, it felt better and better. The idea of my dick being in the dildo's place became more real with every step I took. The dildo was moving at an amazing pace by this point. She was so wet, it has soaked through her panties. Her moaning was loud and continual at this point. Just as I took the final step close to her, I felt the cum approaching releace from my shaft. I wanted to fuck her so bad, the very thought of it made me want to cum. Now that I was within reach I couldn't hold it any longer. My first shot of cum was so powerful it went straight up, with her in her ponytail, and dripped down her back. My second had lost power, and only made it as far as the top of her panties, and dripped down the back of her ass. Just then, her body started to shake. Her whole body was in motion, and then tense and silent for a few seconds. She let out a lout moan and gasp as I pumped the remainder of my cum onto her back and ass. The dildo slowed at this point, and the bussing stopped. She continued fucking herself slowly though. I took the towel, and wiped down all the cum that I had left on her. Then, as she still continued to fuck herself with the dildo, I leaned in from behind and pressed my body against hers. I has always wanted to hold her like this, fulle aroused still, and fully engaged in contact. I reached my arms around and slowly caressed her breasts, squeezing occasionally, and tickling the nipples. My hard dick found its way between her legs, and was resting between her left leg and the dildo that was going even slower now than it was before. I could feel her pussy juices on my dick as the dildo rubbed up against it. We stayed like this for a while, until she decided she had enough. Then speechlessly we got dressed, and waited for my friends arrival.