I feel his fingers lace through my hair and I glance up at him, across his broad muscular chest: his head is leant back, eyes closed in bliss."Mmm," h... moans, "are you sure you've not done this before?"I can't answer him, my lips are wrapped around his thick shaft. I feel his fingers tighten in my hair as he takes control, gripping my hair tightly as he starts to thrust into my mouth. My eyes pressed tightly shut, I focus on him and his shaft, making my mouth the most pleasurable hole he's ever. Slut..."Courtney's voice said as the noises of two bodies humping became louderand faster."Yes... Yes... Fuck... Fuck... I'm so fucking... cloooossseee..."Marissa's voice was groaning before the slapping sounds came to asudden halt.Going with what she was hearing, the real Marissa could picture herpregnant stepdaughter ramming her stepmom's twin with a strap-on. Butthe upcoming exchanges became more and more confusing."No, no, nooo... Why my mistress...? Why did you stop...?" the Marissavoice. I hesitated before moving my hand to my cock knowing to refuse would probably lead to a beating or maybe worse. I looked at my sister, her arms outstretched out to her sides at shoulder height and roped to the rail. And otherwise completely exposed. Her chest stretched by the way she was tied outlined the shape of her tiny tits and her still proud stiff nipples. Her lithe body had little to no excess fat and so her ribs could be easily seen and below that her flat stomach moving in and out with. . Huh? What?" I had a nightmare... I'm really scared"I sat up and realised immediately she was petrified, she was shaking."Oh god; Ok... Do you want to sleep in hear with me?" I asked."Will you keep me safe?" she didn't need an answer as before I could, she was under my covers nestled into my chest.We layed like that for a while, then she turned over with her back toward me.We layed normally there for a few moments, then she started shuffling her ass into my cock and gripping my hand tight to.