My sister Kim is six years older than me, she's extremely good looking and for a woman her age, she still gets admiring looks from men as her body is amazingly fit.

From the age of around twleve years old I began to listen in when she had boyfriends round. I would hear them having sex and I always knew when she climaxed either from oral sex or fom them fucking her, as her orgasm noises were very distinctive.

Three years on I was about to go out when I saw her bedroom door ajar. I knew she had her latest flame round and I could tell they were fucking. Putting my face to the crack in the door jam I could see her bed. Moving slightly Kims naked body came into view. She was sat on the guys cock with her asshole facing me, and she was slowly raising up and down on his cock. Her ass looked perfect as her pussy enveloped his dick. I instantly became hard and in a first I took out my cock from my shorts and began to stroke it.

As Kim started to fuck him harder and faster, so did I, as I masturbated to the view of my own sister having sex. I didn't hear or see him or her cum as I was too busy cleaning myself up. I'd cum all over myself and the floor outside her bedroom, then sneaked back into my own to clean myself.

Later that night, our first night, she asked me to go into her bedroom, telling me she'd follow me up when our mom and dad were watching the movie they'd rented. I was sat on her bed when she entered trying to look inocent. It didn't last long as she said "I knew you were there today. I found your cum stain on the carpet outside my room as well. Did you like watching me and Tim fuck. It was horny knowing you were watching and wanking". I'd been busted and I didn't know what to say. Kim did though, she asked me to show her my cock.

I was fifteen years old. Still a virgin, but I knew my cock was bigger than most of my peers and somehow I knew Kim knew too. When I tried to leave her room Kim said "Don't you want to see my pussy and asshole up close" That was the clincher and the sentence which started our seventeen i****tuos affair.

Undoing my shorts I lowered them and immediately my cock flopped out (I'd stopped wearing underwear about six months prior to our first sexual encounter) Kims face lit up and before I could say no or resist, my twenty one year old sister had her mouth around my cock. It felt utterly awsome as she took in nearly every inch of my flaccid cock. As it grew though she began to struggle with it's girth and bega to lick my balls, then back up to take the glands of my dick back into her mouth. As I began to moan Kim stopped, slipped off the bath robe she had on and told me to kiss her pussy.

I did as I was asked, but I didn't know what I was doing as Kim went back to sucking on my then erect cock. I sort of played along as if I knew what I was doing, but I couldn't play along for too long as my cock erupted filling Kims mouth. The orgasm I had was so sudden and so strong I didn't have time to warn her. Not that it mattered as my sister swallowed every drop. Smiling at me Kim said "Thank you for letting give you a blow job, your cock really is as big as they say. If you come to my room tomorrow night when mom and dad go out, I'll teach you how to make me cum too".

I couldn't wait for them to go out the next night. I knew kim was in her room, but what I didn't know was she'd shaven her pussy bald. Both lay on her bed naked with my cock rapidly rising, kim started my life long love affair with her pussy and asshole, by teaching how to pleasure a woman with my mouth, tongue, fingers and my nine inch cock.

I lost my virginity that night to my own sister and if society wasn't so set against siblings marrying, I would have wed her long before we were expected to form long lasting relationships with other people. As it is we are both married to people who we both agreed the other could marry. Kim and I still get together four or five times a month to renew our love for each other. We also know if one or the other does break up with their respective partners, we just might leave and live together as man and wife anyway.