I can't remember exactly when my sister Cindy and I first began masturbating in front of each other, but by the time we were in high school, we would usually come home after our dates with other people and tell all about what Cindy called "the juicy details." My sister is a beautiful brunette with smallish-sized tits. I'd tell about dry humping my date in the front seat, or touching some girl's tits; and Cindy would sit back against the headboard of her bed and slowly bring her knees up, then open her thighs.
As she listened to me describe my sexual adventures, she'd moan a little, and begin rubbing her pussy through the thin cotton of her panties. While I watched, eventually she'd pull her panties off, let her skirt slide up to her hips and expose her naked pussy to me. By now my dick would be getting very nice and hard while I told what I'd done with other girls. Cindy would put her feet together, sole to sole, and spread open her legs so they formed a diamond shape with her pussy at the top.
Cindy's fingers would slide tantalizingly in and out of her wet pussy until just staring at it made me so hard I'd have to take out my cock and jack off. I'd lean back against the foot of her frilly bed while she lay up at the top and we'd masturbate freely. Both of us watched each other's aroused sex organs as we played with ourselves.
Cindy would pant and groan softly - our parents were always in the bedroom next door - and stare at my cock while she teased her pussy. When she told about touching some guy's penis, I'd straddle her single bed with my legs outstretched and play with my cock, jerking it up and down faster and faster until I shot off into a wad of Kleenex she'd hand me.
For weeks we'd do stuff like that, until finally Cindy said it would be more fun if we masturbated each other! I was kind of shocked, but I liked the idea. So after our other dates, Cindy and I always made a "brother-sister" date for later. Sometimes I'd even take my girlfriend home early so I could meet up with Cindy in her room. There I'd slid up next to her on the bed and help her take off her panties as we "discussed" what we'd done on our dates. We'd lay there with our clothes half off, and I'd unhook her bra and kiss and suck on her tiny nipples, making them hard. I'd slowly rub her pussy with my hand, then when she started getting hot, stick two fingers into her cunt and finger-fuck her slow and lovingly. Cindy would find a way to zip open my fly and get my cock out and rub it good and hard while we teased each other with our stories about sex with other people. Then as Cindy would cum, she'd jack my cock off hard and I'd shoot my cum into her wadded-up panties as she held them against my spurting dick head.
By the time we were both going to the city college, we were no longer virgins except with each other. Oh, we'd progressed a lot, though; Cindy learned how to suck cock, and I loved to slide my head down between her thighs and lick and kiss her pussy until she came. One night we got so carried away we found ourselves naked and doing sixty-nine with each other for about half the night. I was worried that if we kept it up we'd be fucking before long, and that would be wrong. I loved the feel of her small titties mashed against my skin as I sucked her clit.
"What we're doing now," agreed Cindy "isn't incest. It's just sucking and masturbating; but if you put your cock in my pussy, that would be incest! I don't think either of us wanna risk getting me pregnant!"
"I wanna put my cock in your pussy, though," I grinned at her. Cindy blushed and admitted that she wanted me inside of her, too, even if I was just her brother.
We had to agree that while we really wanted to fuck each other, we would make a "contract" not to. If either one of us had a big urge to fuck, Cindy said, we'd just make sure we'd make the other one cum right away by oral sex or something. We both would cum a lot.
After that usually Cindy and I kept our "brother-sister dates" under control. Mostly I'd just lay on the bed with her and suck her tits lovingly while my fingers went in and out of her snatch as expertly as I could do it. Cindy would french-kiss me and rub my dick sweetly until I spurted cum into her hand. Sometimes she'd slide down and kiss the head of my cock, then slowly lick on it and suck it between her lips. I tried hard to hold off, but sometimes I'd just have to cum in her warm mouth. Cindy would groan and then swallow it!
Then one night Cindy came into my bedroom, all breathless and glowing, and I knew she'd really been fucked royally! "I've got the answer to our 'problem', honey!"
"Get your clothes off, brother!" she demanded, giggling and helping me unbutton my shirt. "Boy have I got something to show you! You're gonna love it! It's just like fucking! Actually it kinda is fucking! And you don't have to be in my pussy!"
Already my cock was throbbing to erection as Cindy pulled my pants down and pushed me back on the bed. She laughed and tickled me as we wrestled, until finally both of us were naked and aroused and french kissing on my bed. Pulling my hands off her titties, she rolled over and knelt in front of me, wiggling her naked butt.
"Come here!" she commanded, looking slyly over her shoulder as she reached back and grabbed my hard prick and guided it up between her buns. God, she was so sexy!
"Cindy!" I protested. "We agreed not to... "
"Shhhh!" she hissed, and pressed the head of my dick between her soft buttcheeks, scooting her ass back until the tip of my prick rested at the little puckered gray-pink ring of her anus. I watched my oozing precum paint a little wet trail in the crack of her ass.
"Fuck my ass, honey, oh godd, it's wonderful!" she moaned. "'N it's soo nasty!
Before I knew it my cock head was stretching the elastic flesh of her anus and suddenly sliding inside her rectum. Her asshole was slimy with some gooey lubricant. All I knew was that it was an exquisite pleasure as my cock slid deep into Cindy's asshole. The hot greasy tube of her butt seemed like the tightest, most alive cunt in the world!
"Awwww, yeahhhh!" I groaned, feeling my cock sink deep into her hot ass. It was the most incredibly nasty, sexy feeling I had ever treated my cock to.
"Yeah, ohhh, honey yeah!" Cindy moaned. She shook her ass in a trembling movement, and pressed back against me, kneeling on all fours. She began ramming back until her ass was firmly pressed against my thighs and my cock was seven inches up into her wide-stretched butthole. She clenched her rectum and sent me into heaven! God, the sweet way her anal canal gripped and squeezed my cock made me want to cum immediately. I just groaned and lay my chest across her back, stroking slowly back and forth in her butthole as I reached around and fondled her swaying, naked little titties.
Cindy hissed and made oval motions with her pelvis as I filled up her ass and fucked it harder and harder.
In no time at all I was orgasming. "Ohhhhh, goddd Cindy, I'm cumming! I'm cumming in your ass!"
"Me too, unnngggg!" she panted, "I'm cumming too! Awww cum in my ass!" Cindy had two fingers in her twat as she supported herself on one arm. I went rigid and poked my cock deep into her pussy-like ass orifice. Then I was spurting squirt after squirt of sperm into my sister's guts; and she was whining and moaning and orgasming as I shot!
Later that night, Cindy rolled over where we were sleeping together and slid under me, she got me hard again by kissing me and feeding me her titties. When I was fully erect my sister opened her legs and bent up until her whole crotch was open and exposed under me. I died as she grabbed my peter and slid it down to her butt hole.
"I wanna see your face while you cum in my ass!" she whispered, smiling lovingly up at me. She hooked the backs of her calves high over my shoulders and kept her ass turned up enough so that I could fuck her butt as easily as if it were her pussy. I had never realized that you could ass-fuck a girl like that, but my sister Cindy taught me how. I lay on top of her and fucked her rectum until I came and came. Cindy stared up at me, delighted at the expressions on my face each time I shot my wad!
Her sweet pussy scrubbed against the hair over my crotch, dripping silvery goo down onto my cock and her asshole when she rubbed her clit with her fingers. Her juices lubricated us more as I fucked and fucked her butt until morning.
I guess after that night it's only a question of time before I stick my cock into her pussy and fuck my sister the way we both have wanted to for such a long time. I mean, which is more nasty, fucking your sister's asshole or her pussy? Cindy said both are just fine, and she wants to do it now!