My twin sister Sandy and I grew up in a rural town, population about a thousand or so, and most of the time the only playmates we had were each other. For that and other reasons we were really close. Our parents were pretty liberal too, and it was common to see another family member with little or nothing on, especially in the summers when it was hot. So nudity was no big deal.

Well, not until Sandy started growing these really nice breasts. She had always had nipples, like me, but now they changed. They got darker and more pink and there was an area around them that got darker too. And she grew hair between her legs. I asked her about it one night when I went into the bathroom to take a leak and she was getting out of the shower.

"Doesn't that tickle?" I asked.

"What?" she shot back, drying her hair with a towel. That made her breasts jiggle a little bit, which was very interesting to watch.

"That hair, around your... down there" I pointed.

She looked down and then looked up. "You mean my pussy hair?"

My eyes got big and I whispered "When did you start talking like that? If Mom heard you she'd skin you alive."

She just laughed. "Well, anyway, why don't you ask yourself. Does YOUR hair tickle?"

I looked down and there, around my penis, was hair I somehow had never noticed. I guess I never spent a lot of time staring at my crotch.

Anyway, that's the kind of relationship we had when we were thirteen. It pretty much stayed that way until we turned sixteen. By then Sandy had real tits and her hips had spread out. She was a looker, and I didn't think that just because she was my twin. She had blond hair, like me, but she wore hers in bangs and it brushed her shoulders. Her lips always looked red, but she never wore much makeup. Guys lusted after her all the time, and sometimes my friends tried to get me to set her up with them. But that never worked, because we all knew each other too well, and dates just didn't seem to work out. Everybody tried to "be" a date, when most of us knew everything about each other and had since we were little kids. There was a little groping and kissing, and some of us called each other boyfriends or girlfriends, but it was all very innocent.

I accidentally discovered that if you washed your dick a whole lot while you were in the shower, it suddenly felt so good that your knees would get weak and stuff would shoot out of your dick. In school I learned that was my sperm. We lived in a farming community, so we knew what dicks and sperm were for.

Anyway, us guys talked about sex and about who we'd like to have it with, but other than Mandy Johnson and Rick Edger, who decided to go steady and ended up fucking their brains out until she got pregnant and had to start home schooling, none of us ever got to even first base, much less getting our dicks wet.

So we dreamed, and talked, and grew up and did all the things that thousands of other kids our age did.

Then, in our Junior year, the school announced there would be prizes for the best Halloween costumes at the school dance. As I look back on this I don't even remember what the prizes were, but I do know they were a big deal at the time. So Sandy and I talked endlessly about what we could go as, trying to win the contest. In the end, we decided that rather than dressing separately, we'd have Mom make us a horse costume and we'd both go as parts of the horse. our Idea was that one of us would be just the front part and the other would be just the back part - not connected or anything. My mother laughed and asked us which one was going to be "the horses ass". Then she suggested that we connect the halves and go that way.

Mom was good with a sewing machine and the costume she made was really pretty impressive. One of us would be the front legs and head, and the other would stand behind, being the back legs and, yes, the horses ass. Naturally, the women ganged up against me and I got assigned as the ass.

She got it finished about an hour before we were supposed to head off to the dance, so we didn't have much time to practice. We got into the thing and walked around the living room. We couldn't get our legs in time with each other, and from mom's laughter it was pretty obvious that we looked pretty lame. So I reached out with my hands and put them on Sandy's hips. I pulled myself toward her, shortening the distance between us, and then we could time our legs together. It made the horse look really short, because the back legs were pretty close to the front legs, but Mom, after she quit laughing, said it looked better than before. Our dad came in and asked why the horse was walking like a camel. Did you know a camel moves both legs on one side forward at the same time when he walks? I didn't. But there was no way we could make it work like a real horse, so we did the best we could.

By now I was sweating a lot - it was hot inside the costume, and I could tell that Sandy's shirt was getting damp too. We climbed out of the suit and went upstairs to get ready. I mentioned how hot it was in the suit and she agreed. "There's no way we can spend an hour or two in that thing and not just die from the heat" she said. I agreed, but pointed out it was too late to change plans. Besides, Mom had put a lot of work into the suit.

"Well" she said in a whisper "we could wear less clothing while we're in it."

I didn't see as how that would work and said so.

She had an answer for everything, though. "See, we'll strip down while we're in the suit, and when it's time to get out of it we'll go into the locker room and put some clothes on there."

I allowed as how that might just work.

Which is how we ended up at school, inside the horse suit, her dressed in her bra and panties and me in my boxers. It WAS a lot cooler. We were some of the first people there, so we put our clothes in my locker and got in the suit. No one had seen the suit yet, so when we wandered out on the basketball court no one knew who was inside. We had agreed not to make any noise, and that Sandy would just nod the head of the horse "yes" or "no" to answer any questions anyone asked us.

The CD player started up and we tried to dance. It must have been hilarious. I had my hands on my sister's panty covered hips and we jumped around, trying to dance. It took almost no time for my hands to slide inside her panties. I figured this out about the same time she did and we both stopped cold.

"What are you doing?" she hissed. "Get your hands out of my panties you pervert!"

I jerked them out. "I'm sorry, you were jumping around. I didn't do it on purpose."

She harrumphed and we started dancing again. It was soon obvious that having my hands on her hips wasn't going to work, because they invariably slid inside the waistband of her panties, or drug them down around her hips. All I touched was the sides of her hips, but I knew where my hands were and that was the closest to a real live female pussy they had ever been, even if it was my own sister's pussy.

The inevitable began to happen. I couldn't keep my mind off of where my hands were and my dick started to get ready for a bath. "Good thing I'm inside a horse suit" I murmured to myself. I changed my hands to her waist, which was better, except that even though we were almost naked it was still hot in the suit and we were both sweating, so her skin was slippery.

During a break in the music Sandy turned around and spoke. "Larry, I'm getting tired of leaning forward in this damn head. My back muscles are beginning to burn."

I knew what she was talking about. We both had to bend over a little bit. Mom had put something on the inside of the top of the horse's back that was stiff, so it would rest on our heads. That kept the horse's back straight. But we had to lean forward. This put my face right in Sandy's back and her face in the head of the horse. She could see out through some screened holes, but all this leaning forward all the time was getting very tiring. Acting on impulse I reached forward and put my hands on her shoulders, right where her bra straps crossed them. I hooked my hands and pulled a little bit, putting my face into her back just above her panties. That eased the strain on my back because my head was resting against her back and I hoped it would ease the strain on her back by me pulling back on her shoulders a little. It DID work. "Ooooo that's better" she said with a relieved sigh.

So, while we were walking around, that's the position we were in. Unfortunately, that put my nose right in the vicinity of a nice sweaty teenage pussy, which, by the way, did NOT smell bad at all.

If that's what fish smell like, then I think I'd like to put fish in my diet.

Anyway, my dick stayed hard. Now when we danced she stood up a little and I just kept my hands on her shoulders. Pretty soon though she started complaining that my hands were digging her bra straps into her shoulders. I asked her where she wanted me to put my hands if she didn't want them there. She thought about it a minute and then reached around and undid the bra. She just dropped it down one of the legs. "There" she said "Now it won't hurt." Now I had my hands on naked female teenaged shoulders. This was getting better and better and worse and worse all at the same time.

The gym got crowded pretty quickly and everybody was trying to figure out who we were. They all asked us questions, but Sandy refused to speak and only nodded the horses head like we had agreed on. It was during one of these conversations that the next thing happened. She was nodding yes in an exaggerated way when my hands slipped off of her sweaty shoulders. She had been leaning into them and started to fall forward. I grabbed for her around her waist and my hands ended up full of soft sixteen year old breasts.

I didn't know what to do. I knew exactly what was in my hands, and I knew that Sandy did too. We just sort of froze. Then the person who had been talking to the horse started asking questions again and Sandy had to go back to nodding.

I knew if I kept on holding her boobs she'd kill me, so I reluctantly stepped closer to her and let my hands slide off of them, downward, to her belly button. I pulled on her a little, but now my head wasn't in her back, so it just pulled her against me. Presto, now my almost naked twin sister, whose breasts I'd just groped, was pulled back against her brother, whose rampant hardon promptly poked into her butt.

I was dead meat. I just knew it.

Then the most amazing thing happened. Sandy took her right hand out of the horses head, snaked it around behind her, slid it between us, and grabbed on to what was poking her in the butt. Now I'm quite sure she thought it was going to be part of the costume. I mean I don't think she knew she was going to end up holding her twin brother's cock in her hand. It was almost comical. She grabbed it, froze, squeezed it, let go, moved her hand around from side to side, like she was trying to figure out what else was nearby, and then slid her hand right through the fly of my boxers and grabbed my naked, hard-as-stone cock.

I don't know for sure, because I couldn't see out of the costume, but I know there was a crowd of people around us now. Most people had figured out who everybody else was, or thought they knew, but no one could figure out who WE were. The thing that helped us was that Amanda Jones and Richard Hecht had come as Mr. and Mrs. Death, in long black robes that covered their faces, and everybody thought THEY were US.

Anyway, what I'm saying is that, at the exact moment my sister grabbed my hardon and I had my hands right between her breasts and pussy, there wasn't any opportunity to talk about it, you know, explain how this was all accidental. So my sister thought I was groping her tits and I thought my sister was groping my dick.

Everybody knows that teenagers aren't all that good at reasoning things out. Everybody except teenagers, anyway.

So I slid my hands back up to her boobs. She groaned. I sighed, because she did not let go of my dick. In fact, when my hands slid across her nipples, she squeezed!

I started finding out what a woman's breasts felt like first hand. I fingered her nipples and was amazed to find they stuck out from the breast flesh about an inch! How had they gotten so large? Now she had pulled my dick completely through the fly in my boxers, including my balls and her hand was pulling on my dick, like she wanted me to go somewhere and was leading me by my dick. Then she pushed and I realized she was doing what I did in the shower.

This was not a good thing.

I knew what would happen pretty soon if she kept doing that, and this was NOT the shower, where all that thick white sperm just washed down the drain.

"Sandy!" I hissed "Let go or something bad's gonna happen". I tried to pull back, but she wouldn't let go. She pulled me back toward her and my dick slid right between her legs.

"Sandy!" I hissed again.

"Shhhh" she turned her head. "Just leave it right there." Then she went back to nodding.

Now, picture this: I have my sister's wonderfully soft tits in my hands, and my dick sliding between her legs while she moves her whole body all around nodding that damn horse's head. I began to get the feeling she was messing with me, so I decided to pay her back. I took my right hand and slid it down, over her belly and right into her panties. I just kept going, and ended up with my middle finger stuck right between the lips of her pussy. The funny thing was I felt the head of my dick right outside of her panties with the same finger.

Well, not so funny. Pretty erotic, in fact.

Sandy was breathing hard now. I knew she jacked off in the shower too, but I didn't know how to do it to her, only to myself. So I figured that if it felt good to rub my dick back and forth, it might feel good to her to rub my finger back and forth too. So I tried that and was immediately rewarded with a hiss, then a sigh, and then her butt pushed back at me and she sort of wiggled her hips.

There was suddenly this really wet feeling on my finger and at first I thought she had peed on me. Then I realized that this was what she shot out, like I shot out sperm or something. That meant she was feeling pretty good, right?

So I figured I'd see what else I could get away with. I hooked the finger and felt around until I felt the hole I knew was there. Then I slid my finger into that. I knew there was something called a clit down there somewhere, and I knew it was supposed to be a bump, but that was about it. We didn't get to see any pictures of things in those days. So I sort of rooted around down there trying to feel for a bump, which resulted in my slippery hand rubbing all over her slippery pussy.

First she sort of squatted a little bit, which spread her legs and gave me more room. Then she started shifting her weight from one leg to the other, like she was dancing or something. I felt her hand come down and I thought she was going to smack me and pull my hand out of her panties, but her hand went right over mine, pushed briefly, like she was telling me I was doing a pretty good job, and then went right on to the head of my dick, which was sticking out in front of her about an inch. She couldn't exactly hold on to it, but she cupped under it with three fingers and pulled it up, pressing it against the part of her pussy my hand wasn't in.

Now I know this sounds weird. I mean here we were, brother and sister, in the middle of the fall festival, inside a horse suit, practically naked, fondling the hell out of each other. I mean I think of it now and laugh.

But neither of us were laughing then. Both of us were horny as hell, deep in the throes of hormones that had been long denied, and everything we were doing felt good - and I mean REALLY good.

So it didn't seem all that odd when she pulled her panties aside and pushed the head of my dick right up into the slit I was rubbing the heck out of. She bent down a little bit and I leaned back a little and the next thing I knew the head of my dick slipped right into her pussy. Neither of us actually intended for that to happen - at least I didn't, and when it did we were both surprised.

We stopped everything right then. Just stood there inside that suit, with the head of my dick just inside the mouth of her pussy. Somebody outside of the suit asked us a question - I have no idea what it was, but Sandy's head came up, like she was listening to whatever had been said. Her fingers were still pressing on the bottom of my penis and she pushed them a little harder before removing them, like she was saying "OK, now you just stay right there like a good boy." Then she started nodding the horse's head again, like she didn't have my penis inside her.