It is the one memory that is burned so deep into my brain that I don't believe Alzheimer's could erase it. I wasn't supposed to be there. In fact, I wasn't supposed to be back for three days, which is probably why they were there. They were both naked and her large breasts (I found out later they were a 38D cup) were bouncing as she rode his cock.

He was lying on his back on the couch and she had her hands on his shoulders, feet planted on the couch on either side of his hips and she was moving herself up and down on his cock. I stood in the doorway for almost a minute watching her puffy pussy lips fold in on her way down and open out as she went up before he saw me. The expression on his face got her attention and she glanced over and saw me. I saw her about to say something to me and then I saw her expression change and I knew what had just gone through her mind.

"What the hell, he's seen it, he knows and there isn't anything I can do about it now so why stop."

She looked back down at the man and started moving faster, as if spurred on by having an audience.

"Aren't you going to make him leave?" the man asked.

"Ignore him sweetie. Better yet, close your eyes and pretend it's my husband watching us."

"God, but you are such a slut."

"If I wasn't sweetie you wouldn't be here."

She looked over at me, winked and then got off the man and got down on the living room floor on her hands and knees. She grabbed a pillow off the couch and put her head down on it.

"From behind lover, take me from behind." The man got off the couch, moved behind her and grabbed her hips as he pushed his cock in. She grunted as he stroked into her and then she moaned and pushed her ass back at him.

"So good lover, so hard and so good. Fuck me hard lover, make me cum."

Without any conscious thought I had opened my pants and had taken out my cock and I was slowly stroking it as I watched. I looked down and saw her watching me. She smiled at me and winked at me again and I lost it and shot my load on the living room carpet.

"Naughty, naughty" she said, "Go in the kitchen and get a dish rag and clean it up before it stains the rug."

I went to the kitchen and got a wet dishrag and when I got back to the living room she was up on her hands and knees. Leaning on her left hand she extended her right and scooped up some of my cum on her forefinger and took it to her mouth. She looked me in the eye and grinned as she put the finger in her mouth and licked it clean.

"Not bad" she said, "Not bad at all. Go sit on the couch sweetie. I'll be done in a bit and then we can talk."

I sat down on the couch and watched the two of them fuck for another twenty minutes before the man pulled his deflated cock out of her. She turned around, licked his cock and balls clean and then told him he needed to get dressed and leave.

"But I was supposed to be able to spend the night."

"Things change baby. I have to do some damage control now and it will be better if you are not here. Go on baby, I'll call you later."

He grumbled, but he got up, got dressed and she walked him to the door. When he was gone she came back into the living room and stood in the doorway looking at me. Watching them had gotten me hard again and I was sitting on the couch stroking my cock with my right hand. I still had the wash rag in my left and she walked toward me with those 38s swaying and a streak of cum running down the inner thigh of her right leg. When she got to the couch she reached down and took the wash rag from me and wiped up the cum running down her leg and then she sat down next to me on the couch.

"Okay sweetie, what are we going to do about this?"

As she said that she pushed my hand away from my cock and replaced it with her own.

"What do you mean?" I asked.

"Obviously I don't want anyone to know about what happened here with Tim so what do I have to do to make sure that you keep the secret?"

I don't know where the courage came from, but I said, "I want what he was getting."

"Oh? Little Tommy wants to fuck his big sister? You want to put your cock" and she gave it a squeeze, "in your own sister? Don't you think that would be really, really naughty?"

I reached out and cupped one of her hanging breasts in my hand and said:

"I don't care if it is naughty or not. You are a married woman so what you were doing with Tim is naughty too."

"Naughty yes little brother, but not illegal, at least not to the extent that incest is."

For an answer I hunched my hips up at the hand holding my cock and she giggled.

"Oh you nasty little boy you. If I give you what you want it all stays a secret between you and me; what I was doing with Tim and what I do with you?"

"Yes" I moaned as she increased the speed of her hand.

"Promise?"

"Yes, I promise" I croaked out."

"I'm holding you to it little brother" and she lowered her head and took me in her mouth. It was too much for me and as her lips clamped around me I came and pumped what felt like buckets into her mouth. She kept her mouth on me until I was soft and then she took her mouth off me and giggled:

"You are one up on Tim little brother. He didn't get to cum in my mouth today. How quick can you recover baby? I had planned on fucking Tim all day and most of the night. I'm horny as hell and now he is gone."

Her hand reached for my cock and as she fondled it she said, "Maybe I can speed things up" and she lowered her head and started sucking on me again. I leaned back on the couch and closed my eyes and imagined that what she was doing to me must be what Heaven was like.

It didn't take her long to get me standing tall and then she stopped sucking on me, stood up and said, "Come on baby brother, let's take this to the bedroom."

I got up from the couch and followed along behind her and that was the start of the most sexually satisfying year of my life.

It all started when my dad got promoted and had to move to a different city to take charge of the factory there. I had just started my last year of high school and my mother convinced my dad that it wouldn't be fair to me to make me drop out of school, move and then have to do twelfth grade with a bunch of strangers in a new city. He agreed with her, but what to do with me?

That's when my sister Marlene stepped up and said that I could stay with her and her husband Jeff.

"He won't be any trouble and he can keep me company when Jeff is on the road."

Jeff was a long haul over the road truck driver and he was away maybe twenty days out of each month. I was a little surprised that Marlene had volunteered since we had never gotten along all that well, but then what brother does get along with an overbearing sister who is six years older than he is?

I figured out later that she did it as camouflage. Who would ever suspect that she was fucking other men while Jeff was gone if I was living with her? Hell, I lived with her for two months before I figured it out and I was right there while it was going on. Two months during which I was an unwitting co-conspirator. Jeff would leave on a seven or eight day run and his taillights wouldn't even be out of sight and Marlene would be going out the door.

"If Jeff calls tell him I'm next door at Marci's and take a message and tell him I'll call back, okay?"

Sometimes it was, "They are having a "Midnight Madness" sale at the mall so I might be late. If Jeff calls take a message and tell him I'll call him back as soon as I get home."