I started fucking my younger sister, Jennifer, about a month ago on the night of her thirteenth birthday. I also fucked her best friend, Becca, and Becca's little sister, Debra. Becca is now my girlfriend and she lets me fuck Debra and Jenn whenever I want. You'd think that I've got all the pussy a guy would ever want.

Well, you'd be wrong. I'm fifteen, so my cock is always ready for more. So, where would I find more? Right down the hall. I have an older sister, Tammy, who is seventeen. And I know something about her that she doesn't know I know. She's fucking our dad.

How do I know? Well, my dad is fucking Jenn, too, and even did Becca in the ass before I ever fucked her. I know because Jenn and Becca have told me.

Now, Tammy is a fine looking girl. Being seventeen, she looks the most like the girls in Playboy or Penthouse. She's got nice C-cup boobs (I've looked in her bra drawer) and a figure to die for. She's hot in a bikini. So hot that I want some of what I've seen in her bikini.

And I've been watching her ever since I found out about her and Dad. Every time I see her, I imagine what she would look like naked. Oh, yes, it keeps me hard. Even for a fifteen-year old guy.

So, one afternoon a few weeks ago, I knew Jenn was at Becca's which meant that Tammy and I were alone in the house.

Well, here goes nothing, I thought, as I took all my clothes off and walked down the hall to her room. I stood there and softly rapped on the door.

"Yeah, come in."

I turned the knob and walked in.

"What the fuck are you doing? Get the fuck out of here."

"Oh, come on, Tam, you've seen these before," I said nodding down to my hard cock wavering between my legs. "I just wanted us to get to know each other better, that's all."

"God, you want to fuck me, is that it?"

"Exactly."

"Unbelievable."

Then, she began to laugh.

"Oh, Brad, you are something. Is this how you think you'll seduce your older sister? Really?"

"Well, I hope it's a start."

"Oh, bring that thing over here. Let me see it. You have grown up some since I last saw it. I think you were seven or eight."

I walked over to her bed and she reached out and took hold of my cock, gave it a gentle squeeze and began to rub it up and down.

"That's nice, Tam. Feels really nice."

"God, you're serious, aren't you?"

"Completely serious. I want to fuck you, big sister."

"Well, maybe your timing is right. I was just laying here thinking about how horny I was and in comes you and your nice cock."

"It's all your's, sis."

"Well, you have me at a disadvantage; I'm still dressed," and she stood up and began taking her clothes off.

Her top and bra came off first.

"Oh, Tammy, just stop for a minute and let me look. Oh, you are perfect. They are the best I've ever seen, even in Playboy."

They were. They stood directly off her chest, pointing right at me, crowned with puffed-up, pink nipples that I so wanted to suck. I reached out and felt each one. Oh, they were firm, nice and firm. Warm. Oh, did my cock stick out.

I leaned toward her and put my hand under one and bent and kissed it on the nipple, then ran my tongue all around it.

"Go, ahead, Brad, I love them being sucked."

Well, this was an invitation I was not about to turn down as I pulled the hard nipple into my mouth and began to suck. Her hand went up to my face as she caressed my cheek.

"Mmm, you're making me wet, real wet. Let me get the rest of my clothes off, okay?"

I stepped back and she quickly slipped off her shorts and panties. I stood there looking at my stunning sister.

"Tam, you are so hot, so beautiful, oh, do I want to fuck you. But I think I want to lick your pussy first."

"Oh, you know how to make a girl happy, don't you?" she said as she lay down on her bed and widened her legs to greet me.

Her pussy was perfectly shaved, clean, pretty pink all around and just a shade darker near the center. Her little butt hole also looked out at me from underneath.

I started on the sides of her knees, kissing and licking my way to where I most wanted to be. But I took my time. After several minutes, I was within about two inches of her slit, she was wonderful.

"God, Brad, lick my pussy, oh, you're so close, do it, now, please. I want you to. Right on my pussy lips, please. I'll suck you off if you do."

Oh, she was horny, all right. Well, why not, so I shifted to her slit and began licking hard up and down. She reached down and pulled her lips apart.

"Oh, yes, right there, oh, harder, Brad, harder, oh, please, yes, yes, oh, you're gonna make me cum, oh, don't stop, don't stop. UUUH, UUUH, UUUH, UUUH, UUUH, OHH, OHH, OHH, oh, oh, oh, Brad, yes, oh, baby, yes, that was good, oh, yeah, real good. Come up here so we can fuck," and she pulled me up between her legs, grabbed my hips and my cock was pulled into her.

"Oh, wait, Tam, I've got condoms in my room."

"S'okay, Brad, I'm on the pill, just fuck me, oh, fuck me good."