I washed myself off in the sink took a piss and started back to bed. I noticed my parents bedroom door was open a crack but didn't think anything of i...t at the time. I lay in bed replaying the sight of my moms pussy peeking out as she dried off when I heard another moan from my mom. This time there was no mistake. I had heard that moan enough at the start of every sex event with my parents that I knew what is was. This was a little different. A little softer. I lay there and listened as moan. I started to really suck his cock as I felt thatmassive cock growing so large as the doggie cock beganto swell inside me. I knew that I had both of them onthe verge of cumming as I worked my ass to accept moreof Butch�s cock. He was so deep in me and my husbandscock was starting to throb as I felt the doggie cockstart to expand so deep within me. I felt the big headas it grew quite large as it pounded my womb with itshumongous dog dick.I felt my husband as his cum started to shoot its wadto me,. " I responded.Eager to learn, Gwen asked, "Can the woman move or does the man do all the work?" She can if she wants to by either raising and lowering her butt and thrusting upwards or by rocking her hips backwards and forwards." I said informatively. But, in my mind, I was thinking how much I wanted to show her exactly how it was done.To my surprise, without saying a word, Gwen began thrusting her buttocks upwards as I had described and said, "Like this?"As she did, her sex slid the full. Your stamina was enhanced. You could perform your duty in top condition for long periods of time that would put an endurance runner to shame. Your body was now incredibly flexible and dexterous, similar to that of an Olympic gymnast. Your genitals were altered to remove any chance of pregnancies, a necessity to improve the efficiency of your performance. Your body chemistry produced bio agents that kill off STDs, and a special controllable gland implanted inside you allows you to be able to.