My big sis Serena is a senior and I’m sixteen and a sophomore. I usually stay after school and participate in some of the many activities available but today I didn’t feel well and got home before she did. I was so quiet laying on my bed she didn’t realize I was there. As usual she had some guy with her who she always told Mom she was studying with.

I soon heard some noises that didn’t sound like any schoolwork I knew of so I crept quietly down the hall and her door wasn’t shut. I guess she wanted to hear if anyone else got home. When I peeked through the crack I got a hardon right NOW!

It was real live porn! My view was from their feet so they couldn’t see me but I sure was getting an eyeful! Serena’s knees were up and a big hairy ass was pumping like mad. I could see her pussy stretched open with a hard shaft going in and out, looking all slippery. His hairy balls swung with each stroke and bounced off her ass. I could even see her asshole!

I was almost hypnotized as I watched and my hand was rubbing my rod in time with them. When he pushed hard I figured he was cumming and I quietly withdrew to my bathroom and rubbed out my own load into the toilet. The sound of my toilet flushing got my sister’s attention and she showed up dressed in my bedroom a few minutes later. I was back in bed like I’d been there all along.

“What are you doing home?”

“I didn’t feel good so I didn’t stay after. Leave me alone. I need to sleep.” She closed my door. My hand went back to my dick that was hard again already. My mind replayed what I’d witnessed. Damn!

A couple of days later I hurried home and hid out in the basement where I did some hobby stuff. Sure enough, Sis checked my room to see if I was there. I could tell that by her footsteps. When I heard the bed creaking I sneaked upstairs and tried to get a peek again. This time she was riding reverse cowgirl and I was busted. I’ll give her credit, she was cool about it. Without losing a beat she threw me a kiss and grinned big then shooed me away with a wave of her hand.

A little later after the guy left, she came to my bedroom and sat on the bed while I was at my study desk. What was she gonna do?

“Don’t bother telling Mom. She knows. I’ve been on birth control for six months now. Did you like the show? I didn’t mind you watching but that guy might have freaked out. A question for you – how many times have you spied on me?”

I told her about the first time and she laughed, “So what do you think of your sexy sister? Did you pop a stiffie?” I nodded, red-faced by this talk. Then she shocked me again by standing up and disrobing. “Here, have a good look. You can touch too but I’m still messy down there. You can’t fuck me though. I’d like to but I promised Mom.”

I looked her over and touched a few places which tickled her. “Here, let me show you how to make it feel good for me and not tickle.” That lesson went well for a few minutes, then, “Drop your drawers so I can make you feel good.” She fondled my steel rod and then bent over and damn near swallowed it. My prostate let go and she giggled as well as you can with a mouthful of shaft and semen. “Mom didn’t say I couldn’t do that. I’ll show you how to use your tongue on me when I’ve cleaned up.”

She said I was a quick learner from my lessons when she didn’t have a friend over to fill her pussy. We also talked and she explained some things I’d have never guessed. Like that our mom fucked her older brother through much of high school. It wasn’t a bad experience at all but it might have kept her from learning about more normal reactions to boys. When she went to college she fucked around too much and dropped out in her first year. She met Dad and got pregnant. He left her when she started screwing his so-called buddies who knew when to stop by while he was working. They never did get married and I got started by a boyfriend but Mom didn’t know which one.

So Serena was a half-sister. She laughed and said that’s why we could go halfway to fucking. Mom had a serious talk when puberty hit and got her on birth control so her daughter wouldn’t make the same poor choices she had.

After a while Serena got feeling sorry for me, especially after she arranged for me to watch her fuck from time to time. I got introduced to her boyfriends and there were currently three. One of them was the guy who was her first time and the other two seem to get changed every few months, I later learned. Anyway, she was such a show off that she put me in her closet and would put on a sex show. When they finished she took them in her bathroom and I would sneak out to go masturbate.

After a while she realized that I was kind of being tortured by watching all that action and not getting any of it. So one day she told me to be home right away after school. She came in with Melinda, her best girlfriend who I had known for quite a while too. “Seth, here is your first piece of ass. How fast can you get naked?”

Melinda teased me with one garment at a time until she stood naked in front of me. Serena kept her clothes on since this was her girlfriend’s party. My pecker was pointing skyward by now so the chubby brunette knelt down and got her first taste of it. She teased a little bit with her mouth but had another place for it in mind. My sister sat down to watch as my new playmate pushed me on my back, straddled me, and I became a man of the world as her dark-furred pussy hid my pecker from the light.

I reached up to play with her little titties as she bounced and it didn’t take very many before I groaned my first load into the place nature intended it to go. She didn’t hop off though, and kept moving slowly while I refilled. “Play with my clitty,” she begged. I did that and she shook and squealed with her orgasm. My second one took a little longer but felt every bit as good as the first.

Sister came over to us saying, “That was hot! Now I know why you enjoy watching me so much. Melinda, stay on him because I’m going to get a tongue lashing before we let him up.”

I sure as hell was in no position to complain, nor was stupid enough to do that. Having a pussy at each end got me up a third time and Melinda rocked on top of me to another cum for her but I was just too drained.

My sister never fails to amaze me, as I’ve said before. When Melinda rolled off of me she licked my cock clean and then went down on her girlfriend to taste the juices we had produced. She looked up at me and smiled and said, “We are best friends you know!”

So now I had some after school fun too and my sister would sometimes join us after her boyfriend fucked and fled. Melinda would eat out the cream she’d collected.

Melinda and I would talk while I was recovering. I was curious as hell about her sex history. “You’re awfully good at doing it.” I said one day, “how long have you been screwing?”

She thought for a moment, “More than two years now.” She was 18 like my sister.

I was moving in and out of her again by now, “So how many guys have gotten to be where I am?” I’d never known about her having a boyfriend or even dating very much.

She took a long time to reply this time and her answer was short, “Only one but I’m not going to tell you who it is.”

She had anticipated my next question so I changed another one, “Are you still doing him?” She nodded and my pecker pulsed its stuff into her. One last question, “How often?”

She turned away from me as she whispered, “Almost every day.”

I could tell she didn’t want to say any more so I just kissed her and told her how much I like being with her. That got a big smile and kisses and hugs and a few tears. She said quietly, “I needed that. Thank you.”