An RV trip with Madison

I could hardly move, I was so surprised at what she was doing I could only obey in silence as she urged me to lift my ass then pulled my jeans down my legs. As she pulled a pant leg off my foot I managed, “Jesus Madison, what the hell are you doing?”
She looked frustrated, “Do you want to wake up mom and dad?” I shook my head. “Then shut up and help get these off” she whispered urgently. When my jeans were on the floor she lay beside me and threw a naked thigh over mine. She was moving her leg, flexing it, rubbing mine with the length of hers. The inside of her velvet smooth leg was leaving paths of burning flesh as she moved it, I could feel her body behind the panties pressing on my hip. I felt the imprint of her hand on my stomach under my shirt, by then my cock was straining against my shorts, begging to be free. She put her lips on my ear and again spoke softly “Now you know what I was feeling.”
In a moment of clarity I looked her directly in the eyes and asked “Are you turned on now?”
Her face lit up with a wide smile, her eyes sparkled as she reached under the band of my shorts and gripped my erection. “Yessss” she hissed softly with her nose pressed against by ear. My embarrassment was rapidly dissipating, boiling away from the heat of her body against mine. In less than a few moments it no longer mattered that she was my sister, my mind and body succumbed to the feel of her hand, the press of tits on me so I rolled to my side to face her. My stiff cock was crushed between us and she rolled her pelvis toward me, pressing her groin on it. I reached down and pulled my shorts down far enough that my erection was standing rigid from its home. I caught her panties with my fingers and tugged them over her butt and down her legs. She helped take them off then threw a leg over my hips. The head of my cock was buried in her pubic hair, she put a hand on my ass and pulled me closer. My head was pounding, my heart crashing inside my chest. I felt hot but I was shivering. Madison’s body felt like it was in flames everywhere her bare skin touched mine. I moved my butt back and put my cock between her thighs, sliding along her crack. She gasped quietly and rocked with me as I began to stroke my stiff prick on her sex. She was hot and the shaft of my cock was getting wet and slippery from the fluids flowing from her, my balls were ballooning with the tension building in them. Madison rolled to her back pulling me with her in one swift motion. I went to my knees between her legs and looked down on her in the feeble light from the camp ground lamp post. She grabbed my arms and pulled me over her then worked a hand between us and grabbed my erection. My sister pulled back the foreskin, stroked me a few times then moved my engorged cock around until the head of it slipped into the opening of her body. I responded to the feel of her by pushing into her as far as I could. Madison put her hands on my ass, looked up at me and breathed soundlessly “Stay there, don’t move.”
I was vibrating with sexual anxiety, my body was tight with tension, I had to move. I tried to stay still for her but instinct overcame my will and I began to stroke in and out of the hot soft hole that enveloped my aching prick. She put her hands on my cheeks, locked her eyes on mine and followed my movement with her own. We were fucking. It didn’t register at all that I had just lost my virginity, it didn’t matter she was my older sister, it didn’t matter our parents were just a few feet away, the only thing in the world that mattered just then is what we were doing. It was all new to me. I’d been fantasizing about several girls and knew what I wanted to do with them but now that I was having sex with my sister they vanished from my thoughts in an instant. My entire concentration, my entire life force was focused on my sister. We mashed our bodies together urgently but softly, not wanting to shake the RV. Madison cautioned me to “Be careful, go slow.” We had both felt the results of mom and dad having sex in the back and she didn’t want them to wake up to the same motion. She didn’t have to worry. About the time she warned me to move slower, my balls erupted violently and I filled her with surge after surge of superheated cum. I had never before felt anything like the violent pleasure of ejaculating into Madison that night.