Rob adored his sister-in-law. He fantasized about her, but he felt guilty doing that. She was family. Off limits even for wet dreams. She tested his resolve when she came to visit, though.

She told her older sister that she was still a virgin, but she wanted Rob to change that. To his utter shock, his wife told him to do it. Did she really mean that? Did he dare make a move?

Excerpt -

As we finished the early lunch, my heart was pounding in anticipation. A part of me still doubted this would really happen. I felt like my wife or Kelsie would announce that this had all been a joke. When Celia sat us down in the living room, I almost felt disappointment.

"Okay, you two, I'm about to leave. I just want to make sure you both are still comfortable with this," she told us, sitting between us on the sofa.

I wasn't comfortable. My dick was so hard that sitting with it bent in my pants was starting to hurt.

"If either of you wants to stop, just say so. I don't want you to feel like you have to continue for the other person. Again, it's okay with me. We all know what you two will be doing, and I am so happy for you, Kelsie. Just be sure not to fall in love with him." She said that last part with a smile, and her sister nodded.

"Now, you took your pill this morning, right?"

"Yes, mother. I promise I won't get pregnant for your husband," Kelsie said for comic relief.

"Rob, I thought you might want to do it in her room instead of ours. I put satin sheets on her bed this morning. They're old so don't worry about staining them."

My wife was giving me instructions on how to fuck her sister. This was surreal.

Kelsie leaned over me to pull Celia into a hug. "Thanks, big sister, for giving me this. For loaning me Rob. You have no idea how much this means to me."

They hugged over my lap. The two women I would have sex with that day were over my dick and it throbbed in appreciation.

"Call me when, uhm, well, when you're finished. Don't feel rushed. Take all the time you need. Do it a few times, let Rob show you some different ways. He can be, uhm, creative in bed."

His wife asked him to make her younger sister a woman. She's his wife's sister so it's not really incest. His wife wants him to do it so he isn't cheating. He tried not to seem too eager when he agreed to do it.