Smiling, I simply asked "How about if we have some fun with each other before we try to find out if my penis will fit in your butt?"
Her nipples erected again a little bit as she told me "I'd like that…"; a second later, she pulled back from me before taking my hand and leading the way to my bed.
As we were walking, it finally sank in for me that things would probably actually be easier for Donna than they had been for Karen, for a couple of reasons. First, Donna was physically larger than her sister, so there was less of a mismatch between my erect organ and the opening involved. Second, and more importantly, there wasn't going to be any additional obstruction in Donna's nether opening — we'd still have to deal with the fit, but there wouldn't be anything like a hymen blocking the way once we got past that point. That put my mind considerably at ease, leaving me free to enjoy the sight of Donna's cute, tight little ass moving in front of me.
With both of us already nude, there wasn't any reason for Donna not to guide both of us right onto the bed when we got to it. Once we were laying on our sides and facing each other, my first considered action was to kiss Donna — softly, on the lips, trying to say without words how very much she meant to me. The kiss I got back told me that I'd gotten the message across, and that she felt the same way about me.
We continued to exchange kisses, and although they stayed loving and affectionate, the physical desire we began to feel began to make its presence known. Our first touches were gentle and non-sexual; but that, too, slowly evolved as the level of our arousal and passion increased.
Several minutes had gone by before my hand finally settled over my niece's breast, and a few more passed with my fingertips again delighting in the feel of her warm, firm mammaries before she moved to lay on her back so that I could reach the other, as well. In response, I propped myself up on my elbow so I could reach all of her.
Even as I was reacquainting myself with the most obvious symbols of her femininity, Donna was touching me in return — her hand was in almost constant slow motion as she felt my chest and shoulders, caressing my face and sides, and running her fingertips through my chest hair.
After a while, both of us were breathing heavily enough that kissing became too difficult, and we silently agreed that the time was right to move on to other things. After I'd slowly kissed and licked my way down from her face and lips, I was able to start tending to the smooth orbs of her breasts with my lips and tongue. I softly nibbled every square inch of both mounds before finally taking the peak of one breast between my lips. I found her areola and nipple were already standing out from the rest of her bosom, but my careful and gentle attention soon had them tight and hard with her arousal; then it was time to do the same for their twin. Before I was finished, both of her areolas were puckered, and her nipples standing tall and proud — and faintly glistening with my saliva. When I pulled my head back to admire my handiwork (and the delightful targets of my attentions), Donna told me "I want to do you, now."
I smiled down at her as I answered "Only if I can do you, too."
Visibly delighted, she nodded her head, and I moved so that she could sit up, then continue on until she was on her knees. I lay down, and she let me help guide her so until she had a knee on each side of my head. Looking down at me, she told me "It always makes me feel so excited when I'm over you like this, knowing you can see between my legs. I know what you're going to do and how you're going to make me feel… it makes me so happy, knowing that you love me that much."
What she said touched me deep inside, and I replied "And I feel the same way — excited at seeing you, and knowing that you love ME enough that you're willing to share yourself with me this way."
I'll always treasure the smile she gave me before she leaned forward, and got herself positioned over me. When we were situated so that we could tend to each others desires, I once again looked at the view of herself that she was giving me — the light-colored delta of her pubic hair, divided at the bottom by the cleft of her sex, with the edges of her thin and soft inner lips barely visible. With the source that close, the scent of her arousal was easy to discern, and just as appealing and arousing to me as ever.
Whether by coincidence or design, Donna took me into her mouth as I first slipped my tongue between the delicate folds bracketing her opening; as I began doing what I could to increase her arousal, she did the same for me.
It was my thinking that it would be best if I could bring her to an orgasm before trying to do what she wanted me to, so that she would be at least as physically relaxed as possible so that it would be as easy as possible for her as we found out if my erection could reasonably fit through the portal of her anus; I figured that by taking things as slow and easy as I could would address any other issues.
Though I didn't tell Donna what I figured to do, she seemed to have at least a similar idea in mind — while I was steadily moving her closer and closer to a climax, she gave every indication of being content to simply get (and keep) me erect. Free of any "distractions", I was able to focus my attention on her, increasing her pleasure and arousal even more when I got the idea to move one of my hands from one of her firm buns so that I could use one finger to begin teasing the rosette of her anus. After I'd transferred some of my saliva (and her oils) to it, I was even able to work the first digit of my finger into her — something that earned me a deep moan around my cock as she pressed herself back in response. That little experiment convinced me that she really did think that anal sex was sexy, and that she really did want to try it.
It also proved to be a great help in moving her even closer to an orgasm; as I slowly and gently worked my finger back and forth through her back opening, I could easily tell that she was getting dramatically more aroused, and even closer to finding her release. It didn't take but a very few minutes of that before I felt her begin to tense over me; a couple more seconds, and she let me fall from between her lips so that she could tilt her head back in reaction to the start of her climax. Under my tongue, I found a sudden increase in the availability of her essence, even as I could feel her rectum clenching tightly around the first digit of my finger. Since I wanted her relaxed and not comatose, I refrained from doing anything to intensify or prolong her orgasm -
at least, other than simply lapping up the supply of female juices that she presented to me.
After several spasms had run through her, Donna drew a deep, shuddering breath before telling me "Thanks, Uncle Ted. That was really nice. If you'll give me a couple minutes, I think it'll be okay for us to try the other part."
I gave her labia one last pass with my tongue before answering "Whenever you're ready, honey.", then took the opportunity to rescue the end of my finger from her rectum — which resulted in a soft gasp from her. Letting my head fall back to the bed, I could still see the shiny entrance to her vagina, bracketed by her inner lips. Her clitoris had disappeared back under its cloak, but I still had the orbs of her firm tush to look at, too; I spent the next little while trying to memorize the sight before me, in the hope that it would be the last thing I remembered before I died.
I knew that Donna was about ready for us to go on when I felt her take my slightly-diminished erection in her hand and lever it up before taking the head into her mouth again. It didn't take her long to restore my manhood to its previous glory, and after she pulled her mouth off of me, I heard her say "I think both of us are ready, now…". A moment later, she carefully moved off of me so that she was kneeling on the bed. I sat up, then reached over to where I'd left the baby oil.