Karen was looking at me patiently, waiting to hear what I had to say, when I got my attention back on her. I considered what she said for a few moments before telling her "I don't think that's anything that you really have to worry about, Karen. You're younger than your sister, and it might just be that your body hasn't quite developed to the point that you can feel as good as she does."
She thought about that for a moment, then asked "Could it be that I'm doing something wrong, or that there's something different about me? Donna showed me how she does it, and when she had me do to her what I do to me, it made HER feel good enough to have an orgasm."
Of course I immediately got a vision of the two of them in my head that had my cock hard in about zero seconds flat. Hoping that it wouldn't burst out of my pants, and that they wouldn't notice the sudden bulge in at my crotch, I told her "Honey, I really don't think that a person can do that wrong — I mean, the fact that it feels good means you're doing it right; and if it feels good, then that pretty much says that there can't be anything wrong with you, either."
Completely without shame or embarrassment, she asked me "Would you look at me, Uncle Ted?
To see if there's anything different or wrong with me? Donna and I both looked at each other, and WE can't see anything that we think would make a difference; but you're a guy, and older than us, so maybe you'll find something we didn't know about."
When she asked me to look at her so intimately, I had the singularly novel experience of what I can only describe as my ears blinking — the audio equivalent of a person blinking their eyes when they see something they can't believe.
My first thought was that she was teasing me, or joking, or something else like that. But when I looked into her face, I could tell that not only was she serious about wanting me to look at her there, but she was actually concerned that there might be something wrong with her. It hurt me terribly to see her worried about something that should have been a source of great pleasure for her, and setting aside my misgivings, I told her "If it would make you feel better, or you think it would help, then I can do that."
Following that, Donna suggested "Since we're sisters, it might help if you could look at me, too." — something that left me both surprised and pleased. I turned to look at her, and nodded my head — not trusting myself not to say the things that were going through my mind.
When I turned my head back to Karen, she didn't say a word — she just scooted herself down a little farther, and brought her knees up almost to her chest before spreading her legs as far as she could to expose herself to me. She was soon followed by Donna doing the same thing, leaving me sitting there with two young pussies to look at.
Leaning over put my head in the general vicinity of Donna's pelvis; shifting myself a bit got my head barely a foot from where her hand had been busy so recently. There was still enough of her oils present that I could easily discern the aroma that was hers alone — light, only slightly musky, and fresh. As I began to look at her, she eased her arms to the insides of her legs, using them to help keep her legs apart as she used her hands to open herself up to me. It was easy to see that her labia were just as my fingertip had told me they were — small, somewhat thin, and soft. Between them, I could see the entrance to her vagina; she was holding herself open enough that I could even discern the ring of her hymen. At the top of her womanhood, her clitoris was making a little bit of an appearance from underneath the hood that protected it. Even with Karen needing whatever reassurance I could give her, I still had to take the few seconds necessary for me to memorize the sight that Donna was presenting me.
When I lifted my head from in front of Donna, Karen moved to duplicate her sister's actions of moving her arms to support her legs so that she could use her hands to expose herself to me. As she did, Donna moved her arms and stretched her legs out on the bed. A little wriggling on Karen's bed got me positioned in front of its owner much as I'd been with her sister.
That close to her, I didn't have any problem identifying the unique scent of her arousal, or seeing that she'd certainly been enjoying what she'd been doing — between her vaginal lips, there was a distinct shine from the oils that had escaped her. Though her labia were smaller than Donna's, they were a bit thicker, and easily just as soft. Karen, too, was holding herself open enough for me to see her intact maidenhead; where her labia came together at the top, her small clitoris was only slightly visible. With the excuse of "examining" her, I was free to take the extra time needed to really give her mons and pelvis the kind of look that I wanted to — and was glad I did. Her sex sported a patch of fine, dark hair that extended only slightly beyond the limits of her mound; it was short and sparse enough that the skin beneath was easily visible.
Despite how young she was, I found the sight (and smell!) of Karen's sex (and arousal) almost intoxicating. But I never forgot why I was looking at her, and after I'd committed the view I had to memory, I withdrew and sat up again; when I did, she went back to sitting as she had been before. Looking at her, I made a point of sounding as reassuring as I could manage when I told her "Karen, sweetheart, I don't see anything wrong with you. You look just fine, there; nothing is different about you that isn't different on every other woman that I've seen."
Hearing that seemed to give Karen considerable comfort — at least, at first. But after she had time to think about it for several seconds, I saw how troubled she was as she asked "Then what's wrong? It works when I do it to Donna, but not when I do it to me!"
"Like I said before, it might that because you're younger than she is, your body just hasn't reached the point where that can happen for you, is all. I'm an engineer, not a doctor, but I'd still bet that there are all kinds of reasons that it isn't happening for you that are perfectly natural and normal — and not one of them would mean that there was anything 'wrong' with you."
With Donna and I watching her, she considered that for a bit before looking at me again and wanting to know "Uncle Ted? Would… would you watch? To see if maybe I should be doing something different? I mean, since Donna's older, and she's started having orgasms and everything, maybe what I'm doing is just easier for her, so she doesn't know that I could do it better for me. And if I get, um, stuck, maybe you could kind of try to help me, even?", the tone of her voice letting me know that she wasn't nervous about what she was asking, but that nothing would work.
From the corner of my eye, I could see Donna looking at me as she nodded her head, letting me know that SHE thought I should do as her sister was asking. But it was the anxiety and disappointment that I could see on Karen's face that really settled the matter for me — I wasn't entirely comfortable with the idea, but I couldn't bear the thought of leaving Karen to worry and wonder unnecessarily. I managed to keep my voice even as I told her "I'm not sure I'm qualified to know how a girl could touch herself better, but yes, I'll do it. And if I think there's anything I can do that will help, I'll do that, too."
There was no mistaking the hope on her face when she told me "Thank you, Uncle Ted. I knew you'd help if I asked…"
After that, all there was for me to do was to get myself positioned in front of her again. As I did, she pulled her knees up again (though not as far) and moved her feet and legs apart — not only to make it easier for her to masturbate, but for me to see what she was doing, and how. Next to her, Donna sat quietly, neither moving nor making any noise; her attention seemed to be entirely on her sister. I saw that both of Donna's breasts were coming to some rather pronounced points, telling me that SHE enjoyed watching what Karen was starting to do, too.