I get home about forty-five minutes or so before my middle-school aged sister's bus drops her off after school. So, being a sixteen-year old guy, that gives me the chance to jack-off undisturbed or to view a little porn or both. Usually the latter.

Now, I also have a girlfriend and, well, we're lots more than friends, we've been fucking for about a year. She's on the pill and she's every boys dream: horny, horny, horny.

So, I had a porn tape plugged into the VCR, a tape I got from a friend at school, and was engrossed in it when I heard the back door slam and in walked my sister, Beth.

"Whatcha watching, Brett?" she asked as I fumbled with the remote, trying to turn the damned thing off.

I couldn't so I hopped up and hit Stop, then Eject, and once I had it in my hand, I was also trying to hide the erection in my pants which, of course, was rather obvious.

"You don't have to hide it from me, Brett, I'm old enough to know guys get hard-ons."

"So, you're into it, huh, having sex all the time, are you?"

"No, but I know about it. We talk all the time at school, I know enough."

"Well, I'll bet you don't know crap about it. You're still just a kid."

"I've seen you and Andrea in your room, watched what you did."

"Oh, what did you see?"

Well, I wanted to know, not just to know, but also in case she ever decided for some reason to tell our parents.

"I watched you two for a while, you never saw me but I saw you. I didn't watch too long because I thought you two might see me."

"So, wanna watch us the whole time sometime?"

I'm not sure why that popped into my head but it did.

"You mean while you have sex with Andrea. Doing it and everything?"

"That's exactly what I'm asking."

"Well, yeah, I think I would."

I knew our parents wouldn't be home for a couple of hours more, so I took out my phone and called my girlfriend.

"Hi, babe, you wanna come over, we can have some fun. Um, yeah she's home but it's all right, she wants to watch."

I got an earful when I said that.

"Yeah, look, she's curious, just at that age, you must remember. She knows we're doing stuff and just wants to watch, just see us when we're together."

Andrea seemed unconvinced but not against the idea.

"I know it's weird but maybe it'll get you off even better. Come on," I begged and she relented and was soon letting herself in our front door.

"We're up here in my room," I called out.

When she came in and saw my sister, she asked again, "You sure you want to do this?"

"Yeah, it kind of turns me on, actually. Doesn't it you?"

"Well, yeah, maybe," as she starts kissing me, pushing me toward my bed.

We were already at each other's clothes and I soon had Andrea naked on top.

"Are you sure you want her watching?" she asked.

"Sure, why not, maybe she'll learn something. Come on, let's finish getting naked, let her see some skin."

And, we were soon out of our clothes and I had Andrea down on the edge of my bed, her legs up over my shoulders, my tongue in her pussy. I couldn't see my sister at this point but there wasn't much that Andrea or I had that she couldn't see. She now has certainly gotten a good look at her brother's equipment all hard and ready to go.

I just love eating Andrea's pussy, well, almost as much as she loves me doing it. When we first started going out, as soon as I had her top off and was sucking her boobs she asked me to go down on her. It was something that her older sister had told her about and how good it felt. Well, Andrea loved it and still does.

"Mmm, oh, babe, I love you doing my pussy, mmm, yeah, right there, ooooh, don't stop, mmm, yeah, yeah, oh OH, OOH, OOH, AYYE, AYYE, UH, uh, mmm, oh, oh," she cried out as she suddenly tensed then began shaking and trembling. I loved giving her orgasms because she responded so strongly, so dramatically to them.

I raised up and looked over at my sister who was sitting at my desk with a pillow in her lap and a hand underneath it. Her panties were puddled around her ankles.

"How do you want to, babe, you name it?" I asked my girlfriend. She didn't answer but just got up on her hands and knees so I knew she was up for doggie-fucking, her favorite. I crawled up behind her and held myself steady, put my dick right up on her wet slit and pushed inside.

"Mmm, just what I want, Brett, oh, yeah," she groaned as she moved her butt around as I began stroking in and out.

"Mmm, you're so juicy, god this feels good," I moaned. I knew, the way we were facing that my sister had a great view of my dick sliding in and out of my girlfriend's pussy. I looked over and said to Beth, "You know, you don't have to hide what you're doing. It's all right with me," and I turned back to my main order of business, fucking my hot girlfriend.

"Oh, Brett, baby, mmm, your cock is so good," Andrea moaned as she dropped her head down on the bed. I looked back at Beth and she had her skirt hiked up and her legs open, running two fingers in and out of herself, gazing at us fucking on my bed.

"You like watching us, Beth? Pretty hot, huh? Your brother fucking his girlfriend?"

"God, it is so hot, you two are awesome," she said as she rubbed herself.

"You don't have to stay dressed, you know. You can get naked like us, join the party," Andrea said over her shoulder. I kept pumping in and out of her, then looked over and my baby sister was sitting in my chair, totally naked, her feet up on the seat, knees wide, running two fingers in and out of her pussy. Did she look hot. My own sister.

Andrea was moving her butt around as I fucked her and it was feeling so, so good.

"I'm really close, Brett, go a little faster. Mmm, yeah, just like that, it's ... oh, OH, OH, AYYE, AYYE, MMM, mmm, oh, mmm," she groaned and collapsed down onto the bed as I moved down with her, fucking her as I went.

"Oh, god, hold still, babe, I'm gonna cum," I cried out as I shoved hard into her, spurting her full of my cum. "Oh, yeah, UUH, UUH, UNH, UNH, uh, uuuh."

Wow, it was so good, I just love fucking Andrea, she is so good, tight, really hot in bed. I pulled my happy, wet cock out of her and slid down next to her as we heard my sister getting off.