"So ya wanna fuck?" the twenty-three year old redhead asked me as she stood in the doorway of my room and smiled.
"Sure Mary," was my response. I threw back the covers of the bed on which I was laying. This exposed my hardening cock.
"Let me just go put Dan Jr. to bed and I'll be right back."
She left and went to put our four month old son in his crib and tucked him in for the night. Five minutes later she walked into back into the bedroom completely naked. My hard dick was already waiting for her. She came up to the bed and straddled me facing forward. The opening of her vagina was at the head of my dick. She slowly slid down. When our pubes meshed she let out a moan.
Then she said, "you fill me up so good bro. Are you going to give me another baby?"
"I have almost a months worth of sperm saved for you."
"I'll definitely be getting pregnant again."
"Yes, I'll give you as many babies as you want, sis."
"Hopefully we'll have a girl this time."
"If not, we can try again, next year."
"How about we try to have a baby once a year for the next six years or so?"
"That's at least seven children, sis."
"I know but I liked that you got me pregnant, and now I want more."
The first time Mary and I had fucked was just after my nineteenth birthday, a little over a year and a half ago. I was visiting her for the summer and staying in the spare bedroom of her apartment. One Friday evening she came to the door of my room and asked, "Dan, have you ever thought about me in a non-sisterly way?"
What do you mean Mary?"
"I'm asking have you ever had a fantasy about fucking me?"
"To be completely honest sis. Yes, I have fantasized about fucking you, many times. Why?"
"Oh, just curious."
"You had to have had a reason for asking me this question. Out with it."
"I heard you jerking off last night, and it made me realize that I am very horny."
"So would you fuck me right now if I was willing to let you?"
"Damn right I would, sis."
"How about it, ya wanna fuck me?"
I answered, "Sure but only under three conditions."
"What are those conditions," asked Mary"
"First of all I don't have to use a condom. Second, I get to shoot all of my sperm inside of you. Lastly, this will be an ongoing thing. We will fuck at least three nights a week."
"I'm not sure if I like conditions one and two, but number three I can agree to."
"If you want my dick in your pussy you're going to have to take my cum as well."
"You could use a condom, please."
"No that point is nonnegotiable."
"What would you say if I told you I don't use any form of birth control?"
"You're not on birth control?"
"Yep. So does that change your mind. Do you still want to shoot your sperm inside your possibly fertile sister and make a baby with her?"
"I told you Mary. If I fuck you I am going to cum inside of you."
"You'd impregnate your own sister?"
"If she wanted me to fuck her, I definitely would."
Mary stood at the door for a second before she walked the rest of the way into my room and then unbuttoned her blouse.
"Okay, Dan, I'll let you fuck me and cum inside of me. I'm too goddamned horny to go another night without a fuck, even if I have to fuck my brother, let him shoot his sperm inside of me and possibly impregnate me."
She stood at the foot of the bed and unzipped her skirt. Mary was now only wearing her stockings, panties and bra. She then removed her bra and tossed it to me. I caught it and tucked it under my pillow. I took a look at her nicely proportioned 32C tits. Mary then slid her panties down her legs exposing her shaved pussy to my eyes for the first time. When her panties hit her feet she kicked them at me. I caught them as well and they quickly joined her bra under my pillow.
"Aren't you going to invite me to join you in bed?," she asked.
For a response I flipped back the covers and she got to see my 7 inch erect cock for the first time. Mary slowly climbed into the bed with me. Our lips met tentatively at first and then we became involved in a very passionate kiss. Meanwhile I maneuvered my dick to her pussy and touched the head of it to her entrance. Mary gasped as she felt the contact. I began to push and I felt my cock begin to sink into her depths. Slowly my dick made its way all of the way into her vagina. My balls slapped against her pussy lips.
"I can't believe I'm letting my brother fuck me," she whispered but loud enough for me to hear.
I pulled back a little and thrust back into her.
"Mary, I'm probably not going to last very long this time."
"That's okay, Dan. We have plenty of more time to practice."
I took a few more strokes and thrust into her one more time before I let my first load of sperm for the night go into her womb.
"Oh, my god. You're cumming in me. I know you said you would. But I still find it sort of hard to believe that you would actually would do it."
"I'm doing it for you, Mary."
"What are you doing for me, Dan?"
"Dan, I do want to get pregnant sometime soon."
"I know Mary. I read your diary."
"You read my diary?"
"Yes," and then I quoted from the book, "'Dear diary, ever since I broke up with Michael, I've been trying to find another boyfriend. But what I'm not going to tell him is that I want to get pregnant within the next three months. I have been off of the pill for just about a month and a half, so I should be ready any day now.' That was from two days ago. Yesterday it said, 'Dear diary, I heard Dan masturbating again tonight, God I am so horny, I might even have to fuck him.' Do you need to hear anymore."
"No, Dan, I don't."
We now lay side by side with my deflating dick still wedged in her pussy.
Mary and I relaxed in the bed for about twenty minutes and then I began to kiss her again. This time I moved down to her tits and sucked on them for a minute.
"Our baby is going to have fun with these," I said.
Mary replied, "Our baby, that sounds nice."
My dick was almost back to fully erect status so I now began to pump Mary's pussy again. This time my sister and I fucked for at least thirty minutes and went into a few positions, including doggie, cowgirl and missionary. She reached at least two orgasms before I blew my second and final load of the night into her. I removed my dick from her pussy and then lay back on the bed.
Mary wrapped her arms around me and said, "thanks, Dan."
"Thanks for what?"
"Being willing to love me."
"You're my sister. I'll always love you."
"Not that way. Like a man loves his woman. I want to be your only woman from now on."
"Yes, Mary. From now on you will be my only woman and I will be your only man."
I got out of bed and made a quick dash to the bathroom and then returned to the bed. Then she did the same. When she came back to bed, she pulled off her stockings which partially stuck to her legs. After removing those my sister got back into bed with me.
Mary and I lay next to each other just content to hold one another. We slowly drifted off to sleep.
When I awoke the next morning I was alone in bed. I got up and heard the shower running so I went into the bathroom and open the curtain. Mary stood under the water. She smiled at me, so I stepped into the stall with her and closed the curtain. We didn't make love under the shower yet. That would come at another time.
Five minutes later we got out of the shower and dried each other off with two towels. She walked out of the bathroom and headed back towards my room.
But I stopped her saying, "last night it was my room. Today it's yours."
She smiled at me for a second time and led me into her room. Mary then laid back on the bed and spread her legs for me. I took the hint and climbed on to the bed with her. I brought my head down to her freshly washed pussy and then took a lick along the slit.
"Oh, she gasped. "Do that again."
So I did. I began to thrust my tongue in and out of her cunt like I would be if I was fucking her. Five minutes later Mary shrieked as she reached an orgasm. I pulled my mouth away from her pussy and then crawled up her bed. Our lips met in an aggressive kiss as my now completely hard dick made its way towards her pussy. As the head of my cock reached the pussy it now belonged to Mary said, "Just fuck me Dan, Just fuck me and cum inside of me."
We spent the next three hours breaking in her bed. I filled her womb with two loads of sperm. After that we took another shower. The rest of the day we spent apart, doing our own separate things. When it was time to go to bed I joined Mary in her room, but we didn't make love that night or even the next morning.
As promised Mary let me make love to her on three nights that week and the next, each time I would shoot all of my sperm into her. Six weeks after our first time together Mary and I were out shopping and I saw her put a home pregnancy test kit into the cart. I looked at her and she nodded and then said, "I'm late."
When we got home and put everything away, she took the test into the bathroom and did what she needed to, in order to complete the test.
Several minutes later she came out of the bathroom with a smile and showed me the plus sign where the results were displayed.
"Are you happy? You got me pregnant."
"Of course I am. Are you."
"Yes, the man I love is the father of my baby."
Eight months later Mary gave birth to our son and we named him after me.
The doctor advised me not to make love to her for another three or four months as that she might still me a little fragile inside.
Mary has let impregnate her six times. We have a total of eight children, three boys and five girls. After our second child was born we moved into a house and actaully started sharing a bedroom full time. None of our children appear to have any defects, that might come from a brother and sister coupling. This would be because we aren't blood relatives. Our parents adopted her at a young age when they were trying to get pregnant themselves. They revealed this to us after we told them that she was pregnant by me.
Mary gave birth to our most recent one a little over four months ago. When she came to bed that night she asked me the question that she has been asking me every year for the past six years.
"So ya wanna fuck?"