Madison's Bikini

James and I have been friends since grade school so hanging out at his parents' house during the summer wasn't an uncommon occurrence, what made it weird was the fact that we were both 23 and just graduated college. His parents decided to take a week-long vacation to god knows where and had asked him to keep an eye on his baby sister. I didn't think she needed a sitter, shit she just turned 18 but his parents were over protective. They have a pool, needless to say I wasn't complaining. We were sitting on the patio with the local rock station was blaring in the background and there was plenty of beer to keep us occupied for the rest of the year. I grabbed another long neck out of the cooler when I heard James. At first I thought he was talking to me until I saw Madison in the door way.

"I thought you went to the mall?"

"I did and now I am back." She huffed out a breath of annoyance and I couldn't help but grin. James and Maddy had this hole love hate stereotypical sibling relationship going on, I thought It was kind of amusing watching them bicker half the time. I've known the brat since she was two; it was hard to think of her as anything other than a little sister. That is until I noticed what she was wearing. I froze with the beer half way to my mouth as I took her in. Her barley there baby blue string bikini left little to the imagination. At five foot five her lithe body was hard and soft in all the right places. Her tits were the perfect size for my hands and I could feel my mouth salivating at the thought of locking down on one of her perky little nipples. Before I could check out the rest of her, a painful smack landed on the back of my head. I guess James noticed me checking out his little sister and from the look he gave me he wasn't happy about it. I just shrugged and downed half of my beer. I know its cliché to say but really had never noticed what a hot piece of ass Maddy had grown into. I didn't stick around for very long after that. I didn't think I could hide an erection with her swimming around in dental floss.

James and I shared an apartment a couple blocks from campus. Since he was staying at his parents place for the week I had the place to myself for once. I was grateful, after what happened that afternoon I didn't feel like getting into a fist fight with my best friend. To get my brain and my dick off the thought of fucking Maddy I decided to take a shower. I tried to stop but I couldn't and by the time I was under the water I was standing a full mass ready to blow my load. The image of her standing in front of me with her back firmly against my chest, nose buried in her neck and my hands cupping her creamy tits.... Mmmm.

I put some shampoo in my palm, lathered it up then started stroking my engorged cock. The tugging sensations were bliss. I closed my eyes and let my imagination run wild. Picking up where I left off I nipped and kissed her neck while pinching and pulling on her nipples. I could almost hear her moan. I let my hands run down her body slowly, enjoying the silky softness of her skin. Finding the ties of her bikini bottoms I pulled the strings and let it fall to the ground. My right hand traveled back up to her stomach while the other traveled lower. My fingers dipped in to her pussy and I noticed how wet she was. How hot she was. I ran my fingers up and down her slit, teasing her clit only to back away again. She was getting frustrated but I wanted her to beg. I wanted her weak in the knees begging me to let her cum, to fuck her.

I pressed my fingers to the stiff little nub that made her legs shake; I pressed hard making slow circles. Finally a strangled "Please!" escaped her throat. Without warning I shoved two fingers up her pussy. It's the last straw. I could feel her muscles clinching around my fingers as she came. By that point I was totally lost in my thoughts. My hand was a blur on my dick and I knew I was going to cum soon so I went right to the one fantasy that works every time but that time it was with Maddy. Her long blonde hair wrapped around my fist, with her on all fours doggy style and my dick buried to the hilt in her luscious ass... my balls boiled and exploded sending my cum all over the tile.

Once I started coming down from the high I couldn't help but feel a little guilty. She's my best friend's baby sister. Hell she's practically my little sister, which makes jerking off to the thought of her even worse. But damn that was fucking hot! Jerking off did nothing to cool off my libido. I was hard again but I ignored it as I quickly finished washing and got out. As I was getting dressed I made the decision to avoid going back to James's parents' house. I should have known better. The road to hell is paved with good intentions.