When I was growing up we lived miles from anywhere and when mum and dad went out I had to stay and look after my sister who was about eleven at the time. We had always been very open as we grew up and as she started to develop I found myself looking at her more and more and masturbating dreaming about her. One night when we were alone I stumbled on her masturbating in her room and I was so horny I got my cock out and jerked myself off on the landing watching her through a half opened door. Ever since that moment I was desperate to touch her pussy. A couple of weeks later mum and dad had gone out and we were watching TV. My sister was sitting opposite me on the sofa and every so often I would get a look at her panties as she wafted her legs about. I had a massive hard on and trying to keep it covered in my shorts was difficult.
Then she raised her knee completely exposing her crotch and I could almost make out the shape of her pussy through her little white panties. This was too much so I made my excuses and went to bed, walking past her with my boner sticking out of my shorts which she full on stared at. A while later she came into my room and asked if she could watch some TV with me as she was lonely. Quite often we would watch TV together so this didn't bother me. Moments later my sis said she was cold so she dropped her dressing gown and climbed into bed with me. As she did so I had a momentary glimpse of her dressed in just panties and bra and I had another instant hard on as I noticed her small firm breasts and hard nipples and a gorgeous tight ass. In bed she slid next to me for warmth and I just froze hoping she wouldn't suss my erection. Some time later she had fallen asleep so I turned off the TV and lay there still with a boner from earlier. Seeing my sister in the flesh and now with her lying next to me had woken a whole set of new feelings and remembering watching her masturbate was sending me mad.
Feeling completely horny I carefully turned to face her and started to rub her nipple. Straight away it hardened and poked out of her bra and for the next few minutes I gently touched and rubbed one nipple then the next. Lust had now taken over and my only hope was that she would stay asleep. Judging where her crotch was I and with my middle finger outstretched, I moved my hand down and after an eternity I made contact with her thigh. It felt so soft I thought I was going to explode in my shorts. Slowly tracing my finger upwards I found her panty elastic and followed it to her crotch and began to trace my finger over the soft fabric of her knickers. Shaking with pleasure and fright at what I was doing I moved a little so I could get my hand right between her thighs and I began to rub my little sisters pussy, feeling every fold beneath the soft fabric. I could feel her breathing harder as I gently circled my finger over where I thought her clit might be, suddenly she let out a moan and her thighs parted. Waiting for a moment I put my middle finger back onto her knickers and now I had full access to her crotch. I was almost coming myself as I caressed her and feeling her groove getting damp with her juice. Her lips swelling and stretching the cotton, bulging beneath the tight fabric as I touched and tickled her.
It was obvious she was now awake as her breathing was heavy, she was moaning and had her legs spread even wider apart digging her heals into the bed. Too far gone to worry I began to hump her thigh for my own pleasure as I worked her panty crotch over her pussy and feeling her dampness now soaking into them. Her breathing was now in time with the rocking of her hips and suddenly he was groping me for my cock. I felt her hand around my hard shaft, then she was pulling me between her thighs and ripping my shorts down, thrusting her crotch against me I pushed my cock between her thighs and began to pump against her panties, moments later as the warm moist cotton made contact with the head of my penis I exploded, at the same time she locked her thighs around me and jerked her hips against mine and we gasped with pleasure. When we had both calmed down I lifted myself off of her, her pussy looked heavenly stuck to her panties. After she pecked me on the cheek, we had a few more nights of lust and one day we both decided we had learned enough from each other and that was that. She still teases me though now and again!