I carefully wrapped her wrists together over her head, and tied them to the headboard. I put a soft blindfold on her. This was a common enough techniq...ue in our sex life that she knew it wasn’t the surprise. After I removed her lacy black panties and bra, I spent a couple minutes sucking on her fabulous tits and fingering her wet pussy. I moved around on the bed, and tied her ankles. I whispered for her to wait, I had to get something. Very patiently, but with a big expectant grin, she waited. My mom works for an insurance company and several months ago was promoted into a new job and she had to go on an overnight business trip not long after taking the position. She had never left us alone much before because her jobs never involved travel before.When Mom told us about her upcoming trip, I immediately assumed that we would be staying alone overnight; she hadn't hired us a babysitter in almost three years. But, she said, since it was overnight, she wanted someone here who had a car. They were changing positions again. Bobby went down on her and suddenly she was quite vocally expressing her pleasure. I could not see his face but I had seen him many times as he ran his tongue over and around my little button. My pussy tingled as I thought of him doing that. I knew the electrifying feeling that Louise was experiencing. I moaned a soft sympathetic moan in unison with Louise. It was obvious that she was enjoying what Bobby was doing. She began to buck and scream like I. Every once and awhile, I would steal a quick glance to see if I could read dad’s facial expressions. But, it was impossible to tell what he was thinking. Even with this pallor of depression hanging over our heads, I found myself also stealing glances at his crotch. In his pants was the cock that I had been sucking for the past few weeks and even though it was very depraved and dirty, there was something that about it that turned me on..Finally, he spoke. Because he mumbled it sounded like he.