The finished basement in our house is also the “computer room”. There are three PCs set up there, two along one 14 foot long worktop and the other across the room with its own worktop. I manned one of the two on the same worktop and my stepdaughters worked the other two. The room was set up such that there was the TV on the far wall, and the two girls were between the TV and me. Allison, the elder, shared the worktop with me and also slept in the bedroom adjacent to the computer room. Brenda slept upstairs in the bedroom beside her mother and I.

The girls, both just having crossed over into puberty, had been browsing porn on the internet and chatting with guys through various programs. I know this because I occasionally scanned their hard drives. Allison even had some near nude and nude selfies, as well as some webcam recordings of guys who were jacking off for her, apparently while they watched her. I had seen none of this activity, although I think I know when she took the selfies.

One night, after Brenda had retired, Allison was sitting at her computer with a shawl type cloth over her shoulder and stretched out to her extended right hand. There was a light shining on her front as she gazed at the computer monitor, casting silhouettes on the shawl. At first I stole glimpses as shadows played on the shawl. Soon enough I realized that I was looking at a silhouette of her uncovered right breast, complete with a beautifully erect nipple. I was careful to watch her without her catching me. It turned out that she was absorbed in her activities and never looked my way. So I just openly watched her as I held onto my gloriously engorged cock within my night shorts under the desktop.

From time to time she would caress her breast and pinch the nipple. At other times she would reach down and rub her pussy over her night shorts, which were not hidden by the shawl. As she became more involved in what she was doing, I became more open about what I was doing. I backed out from under the desktop while stroking my leaking cock, nearly exposing it through the fly in my shorts. I was getting charged up while I found it remarkable that she never looked my way. I was sure that the motion of my arm would have caught her attention, actually kind of hoping it would.

I timed my intensity to measure along with hers. Soon, she scooted her butt up to the edge of the chair and kept her legs parted wide open. She more intently massaged the breast and intermittently massaged her pussy, placing her hand between the seat and her shorts and bearing down on it. I was leaking a steady stream by now, and I don’t know how she didn’t hear the squishing sound as I helped myself. Finally, she clamped her thighs around her hand and threw her head back as she convulsed in orgasmic spasms. At the same time I filled my shorts with rope after rope of millions of little swimmers, looking for her.

Finally, we both were panting as I returned my gaze to the computer, but watched her out of the corner of my eye. Slowly, she closed down her programs and went to her bedroom, leaving her computer on.

I was home alone the next day, so I made my way to Allison’s computer to snoop around. I found three more nude shots of her, two showing her small but hot breasts with incredible nipples, and one of her hairless pussy. I couldn’t tell whether she was naturally bare or if she shaved. Two fingers of one hand were holding open the gates to glory land.

There was also a video from last night, a webcam video. It was a black guy who appeared to be her age with a ginormous dick. From watching him, I knew exactly when Allison and I came. I was hard again. The photos of Allison did not show her face, but it did appear that the photo was taken in her bathroom. I copied the photos and placed them on a CD with an innocuous title.

The next night I waited to see what would happen. Brenda went to her room at the regular time and Allison just sat at her monitor, feverishly typing and reading. The shawl was not in sight. After a bit, she headed upstairs and asked if I wanted anything from the kitchen. I asked for a Coke and she disappeared up the stairs. I opened the photos of her so they would be on my screen when she returned. I heard her returning down the stairs, but I chickened out and closed out her pictures just in time.

Allison placed the can of Coke on my desk, leaned down so that her lips were almost touching my ear and whispered, “Did you like the pics?”

Had not the hot breath from her lips melted me, I would have jumped in feigned protest, but I just sheepishly looked up at her. She said, “I saw those pictures on your screen.” Pause. “And I saw what you were doing last night, too.”

Damn!! When did she see? I never saw her even look at me out of the corner of her eye!! But I knew there was no point in protesting. I should note here that we had caught each other in less blatant positions of sexual enjoyment several times in the past, but nothing was ever said. I would rummage through her room and find thongs that her mother thought she would never wear and move them to another place in her room. When I went back the next time the thong would be in its original place and I would move it again. Nothing was said. On my computer I would find my browser left to a porn site I had visited the previous night, but knowing that I had closed it down. So we both knew that the other was up to something, but, I felt, that we were signaling to each other that we knew and that it was okay. It was like we had a camaraderie together.

So, I looked at her and said, “Well, obviously you haven’t told your mom, and you apparently know that you have been caught in compromising situations, too, so, okay, I admit it. Where do we go from here?”

She stood straight up, poked out her 34a breasts, looked down at me and said, “I don’t mind if you see me or my things.” After a short pause, I responded, “but?”

“But I want to see you.”

I said, “You have, like that time when you came to shut the bedroom door and I was lying naked on the bed on top of the covers, or the time you looked in on me in the shower.”

“How did you know about the shower?”

“I could see you from the bathroom light.”

We both paused, and I was liking where this seemed to be heading. Then, she said. “But I want to see you up close and not having to peek.” Damn, how good could this be? “What do I get out of it?” I asked. “The same,” she replied.

Now, this wasn’t like I was seducing her. I mean, it’s all her idea, right?

I whispered, “We need to keep everything super quiet. Sounds can be heard through the duct work.” She nodded, knowingly. So, again, she lowered her lips to nearly touching my ear and whispered, “I’ll go sit in my chair and we can show each other.” I nodded and she sat down, I don’t remember what happened to the Coke. She sat down and we turned toward each other and spread our legs. Allison pulled her night shorts to one side and gave me the first live view of her pussy. I pulled my boner through the fly of my night shorts and held there for her hungry eyes. It wasn’t as large as the one she had watched on the webcam, but it was at least as hard. We both stared. I started a slow stroke and she started a slow rub and then I began to leak. As the pace picked up we said nothing, but Allison was beginning to be restricted by her shorts. She quickly lifted her butt off the chair and slid her shorts down past her knees. I did the same. We were down low in the seats, legs apart, knees almost touching. Allison rubbed her clit, then fingered her wet pussy, then her clit, again. We were in perfect time. As she went in for the final push, I stroked to the max, and we came together! I aimed my cock at her and got some on her thighs and on both our seats. We reveled at the heights of our climaxes, making the come down as slow as possible.

Then we both just slumped there, looking at each other, spent. Finally, I walked over to her, and lowered my lips so they were touching her ear, and whispered, “I can’t believe I just jacked off in front of my step daughter.” She took her wet hand and put it around my neck and pulled my ear next to her lips and whispered, “But it was so good.”