They had a sort of focal centre set up at one end of the room with the bed and a low table next to each other. Andy had a rather mysterious plastic sh...opping bag placed next to him on the floor. “What’s in there, Andy?” I asked.“Oh just some possible props for Sue to use later if she wants” he winked. Sue looked embarrassed, took a drink off one of the others and sat in the corner.“Are you ready to start, Sue?” I asked “Or do you want a few minutes or a few more drinks?”She took a deep breath.. I pulled them down and a half swollen cock popped out. I looked up at him, and he smiled and nodded. I closed my mouth around his cock and he moaned. As sucked on him, I massaged his balls. Then I took each one of them in my mouth. He started moaning, soon his thick 7” cock was fillling my mouth. I’m taking a much of him as I can handle, soon he has my head pinned against the side of the bed as he fucks my mouth. I am gagging, drool running down my top. “Are you ok” he mutters... I nod, as I am. It was separated from the observation room by a one-way Plexiglas mirror—requiring one room to be brightly lit, and the other darkened to work. The observer section was large enough for twenty people and was fairly crowded, even though Phil, Meg and the first volunteer, Melvin, couldn’t see them.While the university professionals were eager to see how Meg handled creatures she couldn’t see, especially given her age, this was the first test group. That meant Phil had to slaughter at least a few. We got busy picking up and putting things back to normal around the kitchen and living room areas. It was during this that I noticed my sister was looking really sexy. She was wearing a short plaid skirt, with a low cut white button up shirt and what appeared to be a white demi bra. I knew I shouldn't be seeing her in this way, but I couldn't help myself. It was the first time I'd ever seen her in this way. I felt a little ashamed, but very turned-on at the same time. I tried to focus my mind.