Happened a few years ago. I'm sorry if you find it a bit long...
The summer of my sixteenth year was as eventful as any other summer before it. I lived with my parents and my younger sister in a modest suburb, I worked part time for a landscaper which provided me with some spending money, my family and I even managed to spend a week at my uncle's cabin in the mountains. However, it was now August and the summer was slowly coming to an end. Soon school would start, and all my free time would soon disappear into endless hours of doing homework, lacrosse practice, and of course, chasing girls.
It was early in the evening and I was hanging out in my room playing computer games. It was unseasonably warm so I was lounging wearing only a pair of plaid colored boxers in an attempt to keep comfortable. After hours of gaming though, I grew bored and switched off the console and flopped down on my bed and laid there looking at the ceiling for a bit while debating what to do next. Being a typical horny teenager it didn't take long for my thoughts to turn sexual in nature and my hand slowly found its way to the front of my boxers. I masturbated often, usually about 10 times a week. Though I was always told that I was a good looking guy, my experiences with girls were somewhat limited likely due to me being somewhat shy. I was thin and athletic with a smooth swimmers build, a byproduct of me playing school sports for years. I had brownish-blond hair, blue eyes, and a boyish face that often led others to believe I was younger than I really was. Masturbating tonight seemed like the natural thing to do and I resigned myself to doing it, that was until I heard my younger sister, Riley go into the bathroom that connected our two bedrooms.
I heard her turn the water on as she was washing her face and brushing her teeth before heading to bed herself, and I decided to wait until she was gone before continuing with my plans. I was thinking of turning on the TV for a bit while I waited, but before I could even reach for the remote, Riley had stepped into my room snickering with a mouthful of toothpaste. 'Nice boner dork.' she managed while still brushing her teeth with one hand while pointing at my erection with the other as it strained against the fabric of my underwear. I quickly covered myself with a blanket and threw a pillow at her which she easily dodged by ducking back into the bathroom. 'Beat it brat!' I yelled. She quickly finished brushing her teeth and popped back into my room. 'You're the one who looks like he's gonna beat it' she mocked.
My sister and I have always been close even though she was three years younger than me. We always joked around and she would sometimes even hang with me and my friends. She was a bit tall for her age and thin. She had the same brownish-blond hair and blue eyes as me, a trait that we had inherited from our mother. Recently my friends began to start making comments to me about how cute she was getting and this made me feel a bit weird, especially when they talked about her tiny boobs and her tight butt. They were right of course, she was turning into a lil' hottie and I hated to admit it to myself that I indeed have noticed also.
She stood there in my room with a smirk on her face, obviously satisfied with her wise ass comment and waited for my reaction. Yet, now was one of those times in which my friend's comments began to flood my mind. Her hair was in a pony tail, and she was wearing a white camisole top that exposed her taught stomach. It was snug around her flat chest interrupted only by the tiny buds of her nipples. She was also wearing a pair of skimpy white panties adorned with a tiny pink bow on the waistband. They seemed to be made of a silky type of material and clung tightly to her toned, narrow ass.
My face flushed a bit, but I managed a reply of 'What do you want anyway? Shouldn't you be picking out what bra you want to stuff tomorrow?'
She grinned and replied 'I only wanted to borrow a few CD's. That is until I saw that you'd rather be alone so you can 'whack it' you pervert.'
She surprised me by saying that. I was beginning to feel a bit embarrassed and found myself at a loss for words.
Riley spoke again 'It's OK. We all know that you do it?'
'Do what?' I replied not knowing what else to say.
'Masturbate. Mom knows. I heard her tell dad that you keep weird stuff under your bed like porn and lubes. She even said that you leave weird stains on your pillow cases probably from humping them. Is that true? Do you hump your pillows?' she said laughing, enjoying my embarrassment.
I was beginning to feel very uncomfortable having this conversation with my little sister. Yet somewhere within me there was something about it that turned me on a bit. There was something about my little hottie of a sister being so devious and intrigued about my masturbation habits that somehow intrigued me. My hard-on remained at attention in the confines of my boxer shorts.
Riley seemed to enjoy my discomfort and continued to tease me. 'It's OK. It's no big deal. I hear that all boys do it. Well, maybe not with pillows.' She then grabbed my blanket and quickly pulled it away from me leaving me once again clad only in my undies with the outline of my erect cock visible.
'Let it be free! Com'on let's see what you do in here.' she laughed. 'Don't be embarrassed just because you're a perv.'
Riley and I always broke each others stones whenever an opportunity arose. She was merely capitalizing on my situation, and I wasn't angry. But still, I had to defend myself somehow. Not knowing what else to do I sprang from my bed and started to ferociously tickle her. If there's one thing that Riley can't stand, it is to be tickled. She instantly howled with laughter and collapsed to the floor, bringing me down on top of her.
'Aaahhh! Stop it! Please please please' she cried with laughter. I continued to tickle her for awhile longer as she tried her best to fight me off.
'Arrghh! Get off me you asshole!' She laughingly cried as she tried to wriggle away from me. She was on the floor on her stomach near my bed. I stopped my barrage of tickles and climbed atop of her and pinned her down by her wrists.
'Get off of me you ass or I'll tell mom you're hitting me! Or I'll tell her that you're up here humping pillows.' she panted.
'Hey you started it coming into my room being a big brat.' I coyly replied.
She was calming down a bit but was still breathing heavy.
'You're such an ass. Please get off of me.' She whimpered.
She wriggled a bit more in a vain attempt to escape. However, her struggle caused something to happen that we both became suddenly aware of, and that something happened to be my hard-on. While I was wrestling with my sister and tickling her, it never went away. If fact all of that physical contact with her cute body only caused it to become even harder and more pronounced, something that I started to feel ashamed about. This eventually resulted in it popping out of the open fly of my boxers only to rest upon her panty covered ass.
'Is that what I think it is? Oh my God!' Riley exclaimed.
'Shit! I'm sorry Riley! It was an accident. I swear!' I replied. I was mortified and began to burn with embarrassment. I loosened my grip and began to get up off of her.
'Wait!' Riley replied to my surprise.
'What?' I asked.
'It's OK... I... uh...I don't mind really. Actually I'm flattered.' She said looking over her shoulder at me with her striking blue eyes.
'What do you mean?' I asked.
'I mean...it's OK...You may like it better than a pillow. Like I said, it's no big deal...All boys do it right?' She said, and then surprised me by arching her butt so that it pressed against my cock. I wanted to get up and leave right then, yet there was something so primal and tempting, that it would not let me go. Riley look amazingly hot, and my instinct took control of me. If she was OK with it, then I could not deny myself anymore. I gripped Riley by her wrists once again and slowly thrust forward gliding my cock across the silky material that covered her perfect ass. I continued to keep her pinned and began to slowly increase my pace. Each thrust forward sent intense shockwaves of pleasure throughout my body. My cock glided perfectly between her satiny cheeks. Riley responded by following my rhythm and arched backwards to meet every one of my thrusts forward. I began to moan softly. I could feel her body heat through the thin fabric of her panties. After a few minutes Riley spoke.
'My arms are going to sleep down here. Can we move to the bed? I mean if you're gonna perv all over me I can at least be comfortable right?'
I smiled and stood up. Riley followed standing up and rubbed her wrists. I then removed my underwear and my erect cock pointed outward. This drew a comedic reaction from her. 'I thought you'd have hair there.' She said snickering and pointing at my smooth pubic region.
I don't say anything back to her and operated out of pure instinct. I grabbed her and turned her towards my bed and bent her over at the edge so that her feet were still on the floor. I grabbed her wrists again and then held her arms in place behind her back by them. Her face was mashed against my mattress and she winced slightly. I advanced upon her and pressed my now throbbing cock again against the fabric of her prefect panty covered ass. I leaned forward and began to hump slowly at first, but soon my rhythm began to increase. Riley's head was to the side and she began to groan softly with each thrust forward. The silk of her panties electrically charged my burning member beyond my control. Waves of incredible pleasure engulfed my body. My cock continued to slide forwards and backwards along the sleek valley of her pantied ass cheeks. My body began to shiver as I felt my orgasm building like tsunami. I continued to hump, yet fought to prolong the imminent release. I let go of Riley's wrists and she immediately brought herself up on her elbows. My body tightened and I could feel myself getting ready to climax. I grabbed her near the waistband of her panties and pulled her backwards to meet me as I humped forward. Soon huge, hot streams of cum burst from my cock one after another. I moaned as I continued to thrust deep as each jet of semen shot forth. I soon slowed my pace and stood, looking down to see two more huge spurts of cum spray along the silken white fabric of Riley's panties, which were now soaked through with huge gobs of my hot semen.
Spent, I turned and slumped onto my bed laying on my back, my softening cock still oozing trace amounts of sperm. Riley stood and removed her underwear with a slightly amused, yet bewildered look on her face. She soon stood there naked from the waist down holding her now soiled panties out in front of her.
'Well that was interesting....Eww! You made a friggin' huge mess you pervert.' She said referring the soaked material on the backside of her panties.
I was still in shock and awe about what happened. But somehow I managed a wise ass response of my own.
'I thought you'd have hair down there.' I snickered as I pointed to her hairless nether region.
'Ha-ha dork. Here you can keep these as a souvenir.' she said while throwing the damp panties at my face before walking out of my room.
'What about the CDs?' I asked.
'I'll come get them some other day. You look like you need some time to recoup. Maybe tomorrow and I can 'get the CDs' again' She said walking away laughing leaving me to look at her faultless naked ass as she exited back through the bathroom door towards her bedroom.