She couldn’t be serious; surely she had to be kidding, right?

Emily looked at Jenny in shock and was silent for a few moments. Then a smile formed on her lips.

“Well, if that’s what we’ll have to do…” she said softly.

“Then what, Emmy?”

“Then… I’ll let him do that”

I nearly chocked. “What?”

“Fuck me, Tom” Emily said again, loud and clear.

I was dumbstruck and even Jenny didn’t seem to know quite what to say. I guess she had never expected that Emily would accept her challenge. I couldn’t believe it either. But, though my ears may have fooled me, my eyes certainly didn’t. While I stood there stupefied, Emily had already unzipped her skirt and let it fall on the floor. Next she hooked her thumbs in the waistband of her white cotton panties and let them drop as well. She was completely naked now, save for her small white socks.

Damn, she looked hot.

While I was still fighting with morality, my cock had turned into solid concrete and was pushing out the front of my pants, much to my sisters’ liking. Emily’s nimble hands had soon loosened my belt and undone the buttons. By now, Jenny had joined her sister and together they had me undressed and led me to the bed, where Emily lay down for me, her legs parted and her knees slightly raised.

She looked incredibly beautiful and incredibly ready as she lay there, completely naked and fully exposed. It wasn’t the first time she had been naked before me, but never had she been splayed out like this, and never had she looked at me with such cum-hungry eyes. I knew that what my sister wanted me to do was wrong, but… well, pussy is pussy, and this was some of the finest pussy I had ever seen.

All rational thought seemed to fade as I guided my cock towards Emily’s very aroused pussy.

“Ready?” I asked, feeling as nervous as if was about to fuck my very first girl.

My sister nodded and I pushed. Her delicate pink lips parted and I slid in about an inch. Emily inhaled sharply as I entered her snug pussy. She wasn’t a virgin, but was just as tight, and incredibly wet.

She looked deep into my eyes and begged for more as I fucked her with short strokes, pushing in a little deeper every time. As my pubic bone finally kissed her smooth mound, I was all the way inside her and I could feel I was filling her up completely. The tip of my cock nudged against her cervix while the ring of muscles gripped me at its base. I gave Emily some time to get used to having me inside her, then pulled out a little and pushed back in.

She whimpered softly and looked at me with her beautiful big eyes, telling me to go on, to keep fucking her. The wet noises of our coupling were all but drowned out by her ragged breathing and soft little moans. Her pussy seemed to cling to my cock every time I moved out, as if her body was unwilling to let me go, now that she finally had my cock inside her.

Although the plan only called for me to inseminate her, there was no reason why we couldn’t enjoy ourselves along the way. My sister must have thought something similar, because after a minute or two of fucking with me on top, she grabbed my shoulder and rolled me onto my back.

Having Emily on top of me was the most sensational view imaginable. She sat upright, leaning back slightly and supporting herself with her hands on my legs. Her immaculate breasts were pointing upward, firm and high, her flat belly taut and every curve of her waist and hips was accentuated by the way she straddled me.

She sat still for a moment with only the muscles inside her squeezing me. Then she slowly lifted herself up from my legs and began to ride my cock. Her breasts jiggled beautifully as she moved. Every time she raised her hips I could see my cock slide almost all the way out of her perfectly hairless slit before she let herself drop again, taking me wholly back in her tight wetness. The view was only surpassed by the exquisite feeling of her velvet pussy and the look of rapture on her face.

Although Emily clearly lacked experience, fucking seemed to come naturally to her. Faster and faster she plunged up and down, fucking towards sexual bliss. Her whimpering turned into moaning and eventually into screaming until she suddenly froze, gasping and quivering as she came on my cock.

Emily kept riding me passionately as she climaxed again and again during the next few minutes, until the pleasure became too much for her and she slumped forward. Her lips met mine and we kissed, another first. I was surprised I enjoyed kissing my sister as much as fucking her. We kissed again and again, our tongues dancing an erotic dance in our mouths while our bodies remained intimately intertwined, slowly moving and undulating as we rolled on the bed.

I had to remind me that this girl was my sister, not my girlfriend! But why was kissing Emily so much better than kissing Suzie or Vanessa? Why was every moan, every barely audible whimper making my heart jump like it did?

Of course I liked Susie and Vanessa, but I never thought of them as a girlfriend. My sister definitely wasn’t a girlfriend. But what did I know, I never really had a girlfriend. I could never find a girl I could really connect with, or one that was as perfect as…

Fuck.

I couldn’t be. Not with my sister.

Just as I realized this, Emily broke off our kiss, sat upright again and resumed her motions. My sister just smiled the most beautiful smile at me as she rocked her hips back and forth.

It’s hard to think straight for a man whenever sex is involved, but this was dangerous and I was running out of time. It wouldn’t be long before I would cum and blast millions of sperms into her possibly fertile cunt. I knew I had done this hundreds of times with Susie and Vanessa without even batting an eye, but cumming inside a harebrained, borderline nymphomaniac classmate was something completely different from knowingly knocking up my own sweet sister!

“I’m going to cum,” I warned her.

“Don’t stop! Cum inside me!” she gasped.

“But you’ll get pregnant! Do you really want big tits so badly?” I said, grabbing her hips to stop her rocking motions.

She said nothing and just kept riding me, smiling mischievously.

I couldn’t do it, this had to stop. Maybe I really was in love with her, but that was also why I couldn’t do it. It seemed our betting and bluffing had resulted in a stalemate.

“Emily, this is insane!” I yelled and pushed her off me. “I don’t care who wins this stupid bet. If you want the money, I’ll give it to you. If you want bigger breasts… Yours are the most beautiful I’ve ever seen! Please!”

Emily said nothing; she just lay there, beautiful and vulnerable. She still looked at me with those beautiful, loving eyes, now radiating with happiness. She had landed on her back, her legs spread wide and her moist pussy looking incredibly alluring.

It was only inches away from my throbbing cock and I really wanted to get back inside. Not because Emily was by far the most beautiful girl I’d ever fucked, not even because her pussy was truly sensational, but simply because she wanted it.

During this awkward moment, Jenny grabbed my cock and aimed it at our sister’s pussy.

“Emily doesn’t want bigger breasts, and she doesn’t need the money” she said. “She just needs you back inside her.”

“But she’ll get pregnant” I objected again.

Jenny just shook her shoulders as she pulled me forward, guiding my cock back between Emily’s pink lips.

“If I can let you cum on me for a month,” she said “then the least you can do is give her what she needs. You owe it to her, and to me as well.”

Then she gave me a final push on my butt and I was again balls deep in my sister’s pussy.

“Now fuck her!” she ordered “And don’t stop until you’re done, I want to see her pussy dripping with cum.”

I gave up. I had tried to talk some sense into the girls and had failed. I started thrusting my hips, pumping my cock in her tight pussy, fucking her faster and faster as I neared orgasm again. This time I didn’t throw her off me, I didn’t stop and protest. I didn’t even warn her, just kept going until my balls exploded.

As my body went rigid, and the first ropes of cum shot up my cock, Emily came as well, clasping me in her arms and locking her legs behind my back, effectively keeping me in a stranglehold while I flooded my sister’s pussy with the biggest load of cum I had ever produced.

Just as I regained consciousness and realized what we had done, Jenny came crawling up to us.

“Don’t worry about it, Tom,” she whispered in my ear, “Emmy’s safely on the pill.”

I looked at my sisters, amazed and confused. Before I could say anything, Jenny laid her finger on my lips. “Have you never noticed it was Emily who watched you fuck those girls, and not me?”

I shook my head, still confused and now feeling rather stupid too.

“Just be nice to her,” she continued, “for some reason Emmy really loves you and she has been dreaming of this moment for years.”

I realized that I was played like a pawn in a game between my sisters, but at this point I was beyond caring. As I looked into Emily’s loving eyes, I saw and accepted the truth why I had liked kissing her so much, and what it was that I had been missing in all the girls I had been with before.

I didn’t have to say anything, nor did she. My lips found hers and we kissed again. As we kissed, it was like part of me flowed into her and I took in part of her.

We were truly one as I started moving inside her again. This time we fucked it wasn’t rushed, not just to satisfy a physical need, but sensually, like lovers. Like lovers who had their whole lives ahead.