I was walking past my sisters' bedroom when I heard moans and low murmurings. Her door was open a crack and I was able to see my sister in her floor t... ceiling closet door mirror. She was spread eagled on her bed with a vibrator being pushed and pulled into and out of her pussy. She was lying on a towel rather than her sheets which I thought rather odd at the time, but I soon found out why it was needed.As she fucked herself with the vibrator I could finally make out what she was saying"Fuck me. Master began to run his hand along my bare thigh. He could see that i was obviously nervous having never done anything like this in my life, so He was kind enough to go slow. He pulled my shirt and bra down, exposing my size 36C breasts. He began to play with them, squeezing and pinching my tender nipples. It wasn’t long before He was sucking on one breast and running his teeth around my nipple, playing with the other breast with one hand and using His other hand to move up under my skirt. I wouldn't be surprised if Keenan and Peter told them, nor would I be mad. Something told me though that he knew about Peter and Kristy, I'm not sure about me and Keenan. But why would he lie if he thought they were innocent?“So how are you?” I ask, really just trying to make conversation. I didn't know him after all.He looked at me and shrugs. “I'm fine.”I nod. “Cool.”We walk in silence for a little bit, but strangely it wasn't awkward at all. It was a comfortable silence, like we didn't need. “A conjuration,” she moaned, lying down on her back. “Hurry. I need your cum in me.”“Now?” I demanded as she spread her legs, her pussy aimed right at me.“We don’t have time to argue!” she snarled. “If we can get across that ravine, we’ll gain so much time. Hurry and fuck me, brother mine.”I stared at my sister in utter bewilderment, my cock twitching to life. Just the sight of her incestuous flesh offered to me hardened my girth despite the danger. An exhilaration shot through me, my shaft.