This is a true story which happened along time ago now. I was about 18 years old and had been out drinking with a few mates. I got in and glad to say my folks had gone to bed so all quiet in the house. I was so horny that night so got a mag out and started jerking off to it.
a few minutes into it I heard the frond door open and quickly pulled up my jeans as my sis walks in, quite pissed herself (Fi was 3 years older big DD tits and a small skinny waist with a firm ass) wearing a mini skirt, she glanced over at me and the mag and looked straight at my crotch, she started to tease me about the mag and turned her back and bent over a little just showing her panties and said its better in the flesh then walked out.
I was amazed, here was my big sis flashing her panties to me, my cock was throbbing and I was thinking a million things when I hear her go to the bathroom. I get an idea and slip into her room and open the blinds, enough for me to see in. I sneak out but my sis walks out of the bathroom just as I was and she says what was I doing in her room, I just asked did she want a quick drink before we went to bed. She says it's getting late and she is hitting the hay.
Fi then leans into me wraps her arms around me and hugs me and holds it for a bit longer than usual and tighter than usual too, all I could feel was her great tits pressing into me and my cock reacted immediately, I know she could feel my cock against her, then she looks at me, gives me a quick peck on the lips as she pushes her crotch against mine then turns and goes to her room.
Now so turned on all I wanted to do was follow her into her room but decided I would at least get to peek at her undressing as I pumped on my now throbbing cock, I rush into the kitchen and out the back door. Fi's room is 2 windows down; I can see the light spill out the crack in the curtain. I sneak up and peek in the window - there is my sis already out her top and skirt, standing in her matching g string and bra. I was glued to the spot my face nearly pressed to the window, and then Fi turns and walks straight over to the curtains looking right at me. Shit I'm caught I think... then Fi stops glances at the opening and turns her back to me. unclasps her bra and lets it fall to the ground, then slowly turns to face me quickly glances at the window, again I think I'm caught, me watching my sis pumping my cock slowly so as not to cum to quick before I see the prize.
Fi then turns again and pulls her panties down bending right over. OMG here is my sis not a foot away bent over and her pussy showing, I nearly fell over kicked something and made a noise. I Freeze, Shit. Fi looks right at the window and then at her dresser chair, pulls it over to face the window pulls something from her locker drawer and sits, spreads her legs over the sides of the chair, her hand moves down over her pussy and I see a vibrator, she starts to rub it up and down her shaved pussy parting her lips with it and sliding it slowly into her open wet pussy, I was so close I could see her wet pussy glisten in the light, I wanted to reach out and touch it or lick it but the glass blocked me, her tits were big, very white and pink hard nipples. Now I can't slow down my hand working faster on my cock wanting to be sliding it deep in Fi's wet pussy. She works the vibe into her pussy and out , up and down her open lips and stopping at her clit after a second or two her clit swells jutting out, fuck me my cock is throbbing my balls tightening as I watch my sis get off right in front of me. Fi's hand now quivering and I can hear her moaning and saying fuck my wet pussy, fuck it hard.
all I could handle, my balls tighten and I feel my load build till my cock spurted rope after rope of cum all over my sis's window, I sip my jeans and sneak back in through the back door, I gently close the creaking back door and turn, to find Fi standing across the kitchen in a dressing gown. I start to say something as she walks straight over to me opens her gown showing me her naked body and says "next time you have to let me watch you cum too" then grabs my semi hard cock through my jeans and gives it a squeeze, then turns and goes, leaving me with my imagination and mind working overtime, I came twice again that night before I drifted off.
I awoke in the morning with the biggest hard on, I turn over and Fi standing by my bed in her gown, she opens it a little showing she was wearing only panties, rubs her pussy through them, then slips them off and hands them to me, reaches under the cover and grips my hard on, wanks it off gently as she says "here at least you can smell my pussy as cum wanking off for me" flicks her finger over the tip of my leaking cock and puts her finger into her mouth sucking the pre cum off her finger, lets out a soft very sexy moan then turns and goes. Fi I call but she doesn't come back. I wank off furiously while sniffing her panties and then shoot my load into them.
I get up slip on my jeans and walk to the kitchen, there is Fi, and my folks sitting drinking a coffee, I walk around get a cup and walk back around past Fi, slip her panties in the pocket of her gown and leave. Later Fi calls me as I walk past her room, I stick my head in and she lifts her dress showing me her panties, a big wet patch showing on her crotch, fuck Fi is wearing the ones I filled with cum earlier. All she says is "your cum is all over my pussy, maybe later ill let you clean it off" but that's another story.