Once she'd given me a few slow strokes, Karen wasn't reluctant to continue for a little longer -
but didn't hesitate to release me when Donna indicated she wanted to continue.
A few more minutes, and I was fully erect… and starting to enjoy Donna's efforts. Not sure what they had in mind, I figured I'd better give them some idea of what they could do by telling them
"Donna, what you're doing feels good for me, and both of you know what it looks like when a guy gets excited. Now, there are a couple of ways we can do this, depending on what you want to happen. Karen, it's up to you whether or not you want to see what happens when a guy has a climax. Donna, if you want us to, you can help me have a climax before we do the other things you wanted to find out about. If you do, then it'll take a little time before I can get excited again
— but, I can do the things that you wanted to learn about between when I climax, and I can get excited again. After that, you can do the things that YOU wanted. So it's up to you two: if you want, both of you can see what happens when I get excited enough, and Karen can leave if she wants; then I can do things with Donna, and we finish with Donna doing things with me. If Karen doesn't want to see what happens, then Donna and I do whichever one she wants to first.
Whatever you decide is fine with me."
They looked at each other for several seconds, then exchanged a few whispers, before Karen told me "I'd like to see.", followed by Donna saying "I want to see, first, so I'm not surprised."
"That's okay — both of you. Now the only thing you have to decide is how soon you want it to happen, and whether or not Karen helps. If you want it to happen sooner, then it would help me if I could touch you more."
I got the answer to the second question when both of them scooted even closer — making it possible for me to reach them from their shoulders on down. What Donna was doing felt good, and my hands were still enjoying the feel of their tight asses, so I just kept going with what I was doing — at least, for a little while.
When Donna released me so that Karen could begin stroking my hard cock again, I figured that it was to me to raise my goals a bit; and more specifically, get my hands on their tits.
When I'd admitted to myself that the other things I'd done with them had been sexual, too, it was as if a weight had been lifted off of me. I was still committed to not doing anything to hurt or disturb them, but I felt like I was finally free to really participate in the things we did together.
So with both of them there with me, and both interested in seeing what happened when I climaxed, I didn't have any problem with seeking out the pleasures that would help make that happen.
Slowly and soft, I caressed my way from the smooth globes of their asses to their hips and waists. After a brief detour to delight in the softness of their bushes, I meandered my way farther and farther up their young bodies until I was finally able to start playing with two very different, but equally enjoyable, breasts. Donna's mammary was still larger than Karen's, but Karen had a slight advantage in firmness. For both, the way I softly drew my fingers from the base of her breast to the tip soon had two small nipples standing proud — one light, and one dark.
Once I'd gotten them to that point, it wasn't long before Karen decided that she wanted to have my erect cock in her hand again; when she started to reach for it, Donna simply smiled at her sister and released her grip on me. After shifting her position slightly, Donna moved to her hands and knees, then leaned over me so that her breasts were right over my face. I was happy to accept her invitation, and raised my head enough to take the end of the breast that I hadn't been touching between my lips, and start gently sucking on it. As I was doing that, I caressed my way down her body until I was able to cup her soft pale mons in my hand. I heard her moan softly when I let the tip of my finger dip between the soft folds of her labia; after wetting the end of it with her oils, I slowly drew it upwards so that I could begin softly and gently teasing her erecting clitoris
— which earned me another pleased moan from her.
It didn't take long for me to get Donna softly panting between the sounds she made as I continued to nurse at her breasts, and patiently toyed with her small pleasure-button. When I spared the time to look, I could see that Karen was fully aware of what I was doing to her older sister — and how Donna felt about it.
Donna had come to me enough times that I had a fairly decent idea of how best to arouse her, and help her have an orgasm. I happily applied myself toward making that happen, but with a little bit of a twist; as Donna got more and more aroused, the supply of her feminine juices increased — and I deliberately let her watch when I would collect a goodly sample of them on my finger, then transfer them to my mouth. The first time I did it, her eyes widened in surprise; but after that, I could see that it excited and aroused her a little more each time I did it.
About the time that I could feel myself reach the point that signalled I was on the "home stretch"
toward finding my release, I felt Karen's hand slowing slightly as she continued to stroke my penis. Another look her direction revealed that she was watching what I was doing to (and with) Donna, more than what she was doing to me. That gave me the idea to try something a bit different than the plan we'd started out with.
I increased the speed and pressure of my manipulations of Donna's clitoris to a point that I knew stimulated her tremendously, and it was barely a minute until I could tell that she was getting close to an orgasm. I waited until I knew she was almost there, then firmly (but carefully!) bit her nipple — effectively pushing her over the edge and into the chasm of a deep and powerful release that had her young body going through a series of powerful spasms. When it was over, I helped support her as I guided her to lay on her side while she got her breath back. Though I kept my head turned toward Donna, I could see from the corner of my eye that Karen was somewhat awed by what her older sister had just gone through — and a bit envious of it.
When her breathing had stabilized, Donna sat up again and looked down at me to say "Thanks, Uncle Ted — that was great!"
I smiled up at her before saying "I think Karen might like to have one, too, before she leaves…"; that was all the prompting Donna needed to change position so that she could nudge Karen's hand out of the way and start masturbating me again. When I turned my head to Karen, I saw that she was looking at me with an expression of uncertainty and desire. I knew how to deal with the desire, and addressed the uncertainty by holding my arm out in invitation.
In almost no time at all, she'd gotten herself to her hands and knees, and close to me; close enough, even, that I was able to gently guide her head down for the two of us to share a kiss — one that ended only after our tongues had played in each others mouths. When Karen pulled her head back from mine, there was a look on her face that I didn't quite know what to make of; it quickly disappeared, though, when I used my hand to tease both of her nipples to erection before sliding it down her belly…
When my hand slid between her thighs, Karen tilted her head back and released a pleased sigh before getting herself situated over me much as Donna had. Again, I welcomed the opportunity to lick and gently suck on the peaks of her breasts, and gently nibble them with my lips. Between her silken thighs, I had started softly drawing the tip of my finger across her opening before slowly easing it up enough to brush it across her erect clitoris. Just a very few passes like that resulted in enough of her oils leaking out of her for me to begin using them to keep from causing her any pain while I twirled my finger around her clitoris, interspersed with periods of gently pressing on it and a slow rhythm. That added stimulation dramatically increased the supply of her nectar; just as I'd done with her sister, I let Karen see as I licked them off my finger after I'd gotten it well-coated. Having seen me do the same thing with Donna, Karen wasn't surprised by it — but certainly just as aroused.