As I described in my story titled "Family Throuple", my wife (Sherri) and I have two college-aged twin girls (Amy and Becky), both living at home while attending the local university. We discovered shortly after their high school graduation that they were engaged in an incestuous sexual relationship which we first ignored then, eventually, openly condoned. By the time they started college, they were openly sleeping in the same bed and conducting their affair without needing to hide it from us.
In the spring of their freshman year, they invited my wife to join them, which she did anxiously. That relationship was quickly normalized and they comfortably settled into a long-term throuple-like sexual relationship which continues to this day, now the middle of their junior year. Sherri always sleeps with me at night, and we enjoy a renewed and vigorous sex life, though there are nights where she comes to bed a little late, having spent some time with the twins. During the day, it's a free-for-all; sometimes a threesome, more often a twosome while one of the three is busy doing other things. For instance, Amy has no classes on Tuesday afternoon this semester, so it's Sherri and Becky by themselves on Tuesday afternoons.
Both girls have told their mother that they are lesbian but Sherri has always thought that Becky was also interested in, and curious about, men. Too many comments about this or that guy being hot while Amy seems disinterested, for instance.
While Sherri scrupulously avoids talking about the details of any given interlude, I've otherwise learned a lot about the twins. I asked once if they both enjoyed the same things, given that they're physically identical, and Sherri said that, amazingly, they were opposite in many ways. Both love clitoral stimulation but Amy likes it light and quick at the top near the hood while Becky likes moderate pressure, lower, more towards the urethra. Amy likes her vibrator at max power with a high frequency; Becky prefers a soft, slow rumble. Amy goes for a girthy dildo; Becky always picks the long one. During cunnilingus, Amy wants a finger on her G-spot; Becky doesn't benefit from it. Becky loves a slow, long kiss; Amy can take it or leave it.
One Monday night a year or so from the start of the throuple, as we were getting into bed, my wife asked if we could take it easy tonight and, so, that night's sex was mild - a few clitoral orgasms followed by her climbing on top for a slow, soft finish.
As we crawled under the covers Sherri asked if we could talk seriously. She said to me that Becky wanted to experience sex with a man; that she wanted to know what it was like; and that she didn't want to toss in her lot with some random college sophomore. I knew what was coming next and I said that I didn't want to be that man. Not only would it put at risk a happy father/daughter relationship, but it had the possibility of doing lasting harm to her sexual well-being. Forget the father/daughter aspect; she HAD come out as lesbian, after all. Sherri was quiet for a minute or so and simply said "Becky is a strong, resilient young woman who has her eyes wide open. She's sure that this is what she wants. Will you at least sleep on it?"
Those words hadn't made it to the far side of the room when there was a light tap on the door and when it opened, there was Becky.
"Has Mom asked you, yet?" she asked.
I told her that I understood what she wanted but that I was unsure for several reasons and that I'd have to think about it. What she said next was manipulative but persuasive. She said "I know why you're hesitant. But all my life you've been there for me when I needed something. I don't understand this fundamental thing about myself and I need to understand it. Please help me with this."
I looked at my wife and she knew. She gave me kiss, got out of bed, lifted Becky's nightgown up over her head and left the room to sleep with Amy. That left Becky standing naked beside the bed with neither of us knowing what to do next.
I knew that having committed to this course of action I had to behave in a way that respected Becky and her needs. So, I got out of bed, stood in front of her and allowed her to look at me. She reached out and touched my chest and, sooner than I thought she would, she reached down and explored me. She lifted my scrotum to explore my testicles; she felt my flaccid penis, feeling the shaft and noting the different feel of the glans; she stroked the frenulum and giggled when I twitched. There was a drop of cum oozing out; she swiped that off and explored the consistency then took it to her lips and tasted, giving it an approving nod afterward. I was happy to stand there until she'd satisfied her curiosity.
She said "Daddy, tell me what you want." and I said "I want to answer your questions."
As she moved to the bed, I was running through what I thought I knew about Becky - clit low; deep; slow; sensual. I'm also screaming at myself not to hurt my daughter and what the fuck am I doing?
