This had been our usual afternoon routine after school for as long as I can remember and I'm not even sure our mom knew as I don't think she ever real...y came upstairs to check on us. We both just stretched out and dozed off.Now you might wonder about this but remember, we had been napping together like this for years and there was nothing at all unusual about it to the two of us.So, one afternoon, we were napping as usual when I was awakened by a rhythmic motion to the bed and opened my eyes to. My cock was throbbing as i plunged harder and harder and breathing was harder and sharper as i neared orgasm i said to Betty "here it cums". She grunted and said "squirt on my belly" so as i felt it about to explode i slipped out and thrust up onto her rounded belly, my seed squirted and oozed over her upper belly and between her big tits which had slid down to the side like saddlebags. There was an almighty roar from Betty as she to reached orgasm and she shook and quivered with pleasure.We. Over the days that followed Jen used my computer but never looked into the mirror. A plan formed in my mind. I would test out the mirror on jen and use her as a test subject and see how far I could go with her.Getting her to the mirror was easy, I just moved our computer stuff to my dressed, her box of floppy disks and mine were now there with my manuals and all my DVD's. Now to test her.After her visit to her friend Jane's house my sister arrived home and asked to use my PC at 10AM. Mom was. "I am so bored" she said"Don't you have plans this evening" You repled. You had finished most of your work for the week and decided to play along."No, I will be alone again tonight" she confessed"It would be nice to make this day go faster" You said "I agree. Did you have anything in mind?" she asks bringing her finger to her mouth and bitting on her pink fingernails in a provocative manner. This was the most suggestive flirting she had given you. All little surprised you tested her. You.