I plugged the corresponding jack plug into the bank of sockets marked positive. I then took a crocodile clip probe and attached the clip end to Serena...s left nipple before plugging its plug into the negative socket.I ordered Stephanie to kneel before me and repeated the procedure on her with the 'A' probe going into her anus. Again the crocodile clip was applied to her left nipple. I told them both, we are now going to play truth or dare. You both answer my questions truthfully or dare to lie. Although the image was no longer on my monitor to study and enjoy, Ifound myself thinking of the beautiful face and the lovely body to thepoint that I couldn't concentrate on the work at hand. My cock remindedme of my interest in the curious photograph; it wasn't just erect, butrock hard, standing, at full length, upright before my belly. How thehell was I to write about soil sampling techniques with such visions ofloveliness in my mind?I felt confused. I'd never been attracted to cross. I began to undo her top, revealing the pretty bra she had on. I unclipped it and freed her nice tits, throwing the bra across the room and squeezed and moulted them while we both looked at him sitting there, helpless.“Hmm, nice tits Kath” I said as I pulled them and rubbed them. Using my fingers, I tweaked her nipples, pulling on them and making them hard. “I love nice tits like your wife's, Mark. Turn to the side Kath, I want Mark to be able to see me sucking them.” I bent down and lifted her. My Mother-in-law was the first to speak.“We must keep this a secret. I don’t know how often we can do this, but I know I want to do it again.”“I agree and I sure am not going to tell anyone.” I replied.As I lay next to my naked Mother-in-law I could not believed what had just happened. Oh sure. I did not regret it. It is just I never thought it would happen. We both agreed this was not lovemaking. It was pure sex and it was exciting. For the next several hours we played with and pleased each.