Inside the box was a pair of black bikinis with a big scarf.I understood they wanted to take me to the beach in bikini and then flirt with me. And the... would spill the beans about my provocative dress up last night if I did not comply. Obviously since I had my mother’s nightie they would be proved correct. I had no other choice but to wear it. As I put it on I realized how much of a slut was I looking. The lace panty rode into my ass crack and covered my pussy well but that was about it as. My step son Zac was already at the table. My wife showed up five minutes later kissing me on the cheek. She had freshly brushed her teeth.I wondered just how far I should push it, and then decided looking at my wife’s mother to not push it. She had let me in on, knowingly or unknowingly, my wife’s plans. I was the cash cow. Her first husband was the sperm donor for one child. Her second husband was a sperm donor for her second child, the kid sitting across the table eating the food I provided. . In a min, she too relaxed and hugged me and smooched me. I untied her hair. She looked sexy in open hair and she has long hair. I took her in my arms and laid her on the bed. She was wearing a nightgown without a bra. I laid beside her and pulled her on top of me. We again kissed. In the meantime, I pulled up her gown and started to rub her ass and back. She gave me kisses on my face everywhere.I made her remove her gown and her two beautiful mango shaped boobs jumped in front of me. I waited. I know. But jeez, it's my mother and no one wants to think about their mother having sex." I had to agree with that and I told her I knew my mother only had sex when my sister and I were conceived. She laughed at that, then she looked up at me, and somehow I knew so I leaned over and kissed her. When I realized just what the hell I was doing, I broke the kiss and told her I was sorry for taking advantage of her. Her only reply was to put her lips back to mine and then to put her tongue in my.