It's 2 a.m. and everyone is finally asleep. I slither from under my girlfriends embrace to go to the bathroom. Rushing to the toilet with a raging boner. The release reminds me of the hot dream of my girlfriend's sister. She was wearing skin tight booty shorts when we were all playing wii sports. Somehow i felt a tension between us earlier, especially when we were wrestling for the good controller. I finish and get cleaned up. Walking back to our room, I pause looking at her room. My heart starts racing and my body is getting hotter as thoughts race through my mind....what if she wakes up....come on just a peek....no...no....go to sleep. I enter her room knocking lightly. She doesn't budge as i check the hall way and leave the door cracked but slightly closed. I tip toe as light as possible to not make any loud creaks with the wood flooring. The journey to her bed side seemed like an eternity as thoughts of turning back while I still can. A huge pocket of air enters my mouth; gazing at the silhouette of her body in the night light. She's in a weird fetal position with a blanket tucked under her chin and hands. Her nicely round ass is poking towards as my palms get more sweaty. I try slowly putting my hand on her ass. Every inch closer to her body increaing tremble in my hands. My whole body stiffens while I place my left hand on her smooth hips and take a deep breath. I withdraw my hand and check the time. Its been a few minutes so I speed things up a bit. The blanket lay loosely around her thighs and hips. A light tug at the bottom loosened an end on the blanket. I peek under to find she's still wearing those tiny little shorts. Her ass was picture perfect as I stare fantasizing of the things I could do to her. Laying undisturbed, I check if she's still sound asleep. I kneel back next to her butt and catch my breath. The nerves are starting to get to me. I test her hip again but this time under the covers. She doesn't move an inch so I caress her ass and cup her left cheek in my right hand; so soft, smooth and firm. I get a closer look of her shorts outlining her beautiful pussy. I placed my middle fingers against her lips light as my hand grasp her ass. Feeling more comfortable by now i start to rub her clit. She twitched a little as i pull my hand away. My heart pounding through my throat praying she doesn't wake. After a moment I get on my feet to keep an eye on her face. I gather myself as I slide my hand back on her ass. I start rubbing her clit lightly and notice she's not wearing underwear. I lick my index finger and place it just outside of her shorts. Sliding my finger on the curve of her butt cheek and under her shorts. My pointer is pressing at the bottom off her lips. I'm rubbing her lips as I keep steady eye contact with her. I slowly remove my hand to taste her. She was so succulent and mild. I slide my hand back under and press my finger against her lips. Her breath is getting heavier as I slip my fingers between her lips. She's getting wetter as I push my finger into her....in.....out...in.........out. when I was done i licked my fingers and left her room and went to the bathroom and jacked off.