He looked as though he was about to faint."Mom? She said that we were ... uh, were ... No she wouldn't!" He said finding himself, refusing to believe ...is mother would give him up that easily, and that I was perhaps fishing, guessing ... suspecting perhaps, but not really knowing the truth. "Because we..." What? Because you haven't been fucking her? Is that what you're actually telling me?" I said, and only then sliding my cock deeply, fully inside his sister's ass, letting him see me as I did. Liza’s legs went limp and she collapsed to the floor and I followed her down continuing to feed her tight virgin ass my pulsating engorged cock. Liza was secreting a milky substance from her ass t appeared to be cum but it wasn’t mine. I placed a folded pillow under her hips lifting her ass enough to provide me with deeper penetration and continued to pound her virgin ass. Occasionally, withdrawing my cock to admire the amazing gape that was once a tight ass bud, I heard Liza’s voice “I want to. The only thing that mattered was that I could tell she liked it. She would pull me into her one minute and try to push me away the next while I clung to her for all I was worth, driving my tongue deeper and deeper. In a short time she was like a wild animal, thrashing and clawing, trying to get away without letting go of me. The effect it had on me was beyond anything I had experienced up to that time and for a long time after. My cock was so hard that I thought it would burst and I couldn’t. I look hesitantly at Diane, and then Jack and I look approvingly at each other. No one says anything. There is total silence in the room except for the heavy breathing coming for us all. After a minute or two, everyone essentially assumes the silence to mean tacit approval. Lucy eagerly reaches out to Jack; taking his hand and promptly leading him through the connecting doorway to HER bedroom. Diane takes my hand and pulls me toward HER bed.For the remainder of the weekend none of us venture.