I pumped and I pumped, my hand surrounding and moving quickly along the full length of my stiff erection as I sat on my sister's bed jerking off.

In my mind I ran images of naked women, though mainly my sister, and I wondered how it would feel to be inside her, to make love to her, something Mom probably wouldn't care to let me do, or even know I was thinking.

I turned to where Mom was sitting in the chair beside the bed, watching me masturbate. My sister Kerri was laying on her stomach beside me, casually flipping through pages in some fashion magazine.

No top on, so I could easily see the curves of her magnificent breasts as they pushed down into her mattress. Kerri saw my glances and as our eyes met we both smiled warmly. Turning on her side for me, I now had an unobstructed view of the most perfect body I have ever seen.

Breasts which were full and well defined, with nipples that stood out like small trees in the center of each of her slightly darker areolas. An absolutely flat tummy, and strong hips which led to her long bare legs.

Now rolling onto her back, Kerri slowly inserted one hand into the thin panties she was wearing and began rubbing herself in tight little circles, masturbating right along with me while our Mom continued to watch.

Kerri cried softly and moaned periodically as she pleasured herself and peaked soon after. I watched as her back arched off the bed a sizeable distance. Seeing my sister in ecstasy is what did it for me then, and I felt a very familiar change inside me as my own orgasm drew near, something which must have shown through on my face as my Mom always seemed to know when.

"He's ready for you dear."

Kerri removed her hand from her panties, licked one of her fingers, and calmly got down from the bed, taking up a kneeling position in front of me on the floor.

My sister grinned up at me and began to open her mouth wide, now ready to take me in. Kerri placed her lips over just the end of my penis as I continued to pump away, quite wildly now.

I came hard to say the least and cried out almost in pain as my semen erupted from my body, flying out into my sister's suctioning mouth. Kerri took several inches more of my swollen member inside her then, and I heard her begin to swallow, quite loudly too, as my rich seed went coursing down the back of her throat.

Kerri closed her eyes and moaned. She enjoyed all three of the full jets I gave up, as well as the steady dribble I produced at the end. She took it all with well practiced ease. After a few more seconds, which my sister spent cleaning the full length of my gradually shrinking erection with her tongue, we were done. Kerri let go of me then so she could lick my spunk off her lips, sucking down every last drop that she could find.

"Good boy, giving your sister such a beautiful body, I only wish I had a brother growing up."

Mom had me feed my sister this way once a day for the past three years, ever since I was 12 and first able. Kerri was one year older, now 16, and a sweet little sixteen at that, with an absolutely gorgeous body, huge tits, and a perfect complexion, all thanks to my credit. Mom believed, and I certainly wasn't going to argue with her, that sperm could give a growing woman the perfect figure, increased bust size, and smooth creamy skin, and she certainly did appear to be right. My sister was going to be a model, like our Mom, and had to be just right for her audition tomorrow.

"Let's have a look at you then dear."

Kerri stood up, turned around, and posed. She always made sure to keep her back perfectly straight, and her breasts stuck out provocatively in front.

"Yes, very lovely dear, but you're not holding yourself quite right, something to do with your hips, spread your legs dear."

Kerri did as she was told and moved her feet apart, placing both her hands on her thin waist. I got hard again just watching my sister's sexy features move around before me, the cleft of her bum catching a hold of the fabric of her panties.

"No, something's not quite right, I just can't put my finger on it though, take your panties off dear."

I had yet to see a woman's vagina and my heart skipped a beat as my sister now pushed her panties down, letting them fall around her ankles before stepping out of them. Still turned away from me however, I just marveled at her smooth little bum.

"Now, spread your legs wider dear, wider."

Any further and my sister would be doing the splits on the floor I thought, as she moved her feet further apart.

"Turn around, let me see your other side."

Kerri turned around and there it was, the secret I had longed to see. I gasped and both Mom and Kerri smiled at me as I took in my sister's thick pussy lips, and the slit they formed between them. My hand went to my erection again, I just couldn't help myself.

Mom meanwhile got down on her knees, placed one hand on Kerri's bum, and with the other began feeling those same pussy lips, actually pulling them apart and now I could see inside a woman's body for the first time. Wetting one finger in her mouth, I was shocked when Mom then drove it all the way into my sister's cunt. So was Kerri, who flinched and doubled over.

"Ouch, no mommy that hurts."

"What, that shouldn't hurt, oh my God you don't mean you're still a Virgin, you answer me young lady, are you still a Virgin?"

"Well, kind of, yeah."

"Oh for pete sake, that explains it then. Now, what are we going to do before tomorrow, I could use my vibrator on you I suppose, but first times are suppose to be special, or at least with a living person anyway and not a machine. So I don't know what we can... Billy, what are you doing?"

"Just jerking off mommy."

"Well, stop it, your sister needs you. Kerri, lay down on your bed."

"Why mommy?"

"Because we're going to fix this right now. Billy, get on top of your sister."

"Mommy?"

"I need you to open up your sister, but don't you dare cum inside her or I'll smack you. That's all we need, your sister pregnant, that would end her career before it even started."

"But mommy, I've never done it before."

"Oh Christ, you too, are you the only two kids not having sex these days? Well alright, I'll help. Now Kerri, lay down and spread your legs for your brother, and once she does Billy you climb on top of her."