"Ron, can you come help me with this?"
My fourteen-year old sister was in a dressing room trying on some jeans and shirts. She had to get some bigger clothes because her belly was growing. She was pregnant. Who the father was, none of us knew. It could be me and it could be one of the many guys she has seduced. It could also be that her horniness day in and day out got herself pregnant and that what was growing in her was a clone of herself. Shit, I hoped so. Despite being fourteen years old, Alicia was very good looking. She was 5'4" at her age, which is pretty tall, and had a nice set of bouncy C-cup breasts before pregnancy and they would only get bigger as she grew up. Her hair was a dark brown with natural hints of red streaked throughout and her face was without freckles. She was a pretty skinny girl as she was very active and had a heightened metabolism and her ass was pretty lean and tight too. Well, at least, all that was true before she got knocked up. Her breasts had swollen a cup size and her belly had obviously protruded, making her ass a little fatter too. It had also for some reason made her hair lighter in color. Anyway, that's my sister for you, crazy things happening all the time.
"What's wrong?" I asked.
"I'm having trouble getting these jeans on," she said.
"Hold on." I took a peek around. No staff was in the vicinity. I ducked into her dressing room. It had a seat and a hook. The door stood off the ground by two feet and the walls reached up to the ceiling. There were mirrors in the corners by which one could see completely around oneself. My sister was still wearing her black shirt which was getting a bit too tight. She had compensated these past few weeks by cutting the V portion of her neckline to give her a bit more room. It was her favorite shirt and she hated having to put it away, but she was learning that being pregnant came with some costs.
I looked down at her jeans. They were too tight, or she was too big. "It looks like you'll have to get larger ones," I said.
"But I like these..." she pouted. Actually, that was the problem. Ever since one of her friends told her about sex a year ago, she had been doing everything in her power to get attention from guys, including wearing tight-fitting clothing. But the problem with pregnancy is that she would keep growing, and despite how sexy it was, she couldn't go to school without pants.
"Well, you're just gonna have to deal with it, Ally. You can't keep buying a pair of jeans for every week. Mom and Dad don't have that money. Here. Put your old jeans on and go get a couple of sizes up or something."
She looked at me with sad puppy-dog eyes. However, she obeyed and took off her trial jeans and started putting back on her old ones. But they got stuck too. "Uh-oh," she said.
"No, you couldn't have grown that big in five minutes," I said. But despite that, her old jeans which she wore successfully in this store weren't coming to her ass anymore. "Let me help," I said. I grabbed onto the rear belt loop and the front of the jeans and pulled up, brushing past her pussy in the meantime.
"I did have difficulty getting it on this morning," she said.
"Well," I grunted, "it's a good- thing- you came- today to get jeans. Tomorrow and you would've- had to wear- Mom's- sweats." I finally got it up, but the button looked like it could go flying off at any moment.
"You know, that looks dangerous," she said, looking down at it.
"Yeah..." I reluctantly agreed. "Alright. Plan B."
"I'm bigger than you. You wear my jeans."
"Okay," she said. She gladly and hurriedly took off hers. I suppose it was probably squeezing her uncomfortably. I took mine off and she put mine on.
"I guess I'll just wait here for you," I said. "Can't really go anywhere like this." Most stores don't like it if you're cock is showing. My sister smiled and left. While she was gone, I started moving my cock back and forth in my hand, bored. Then I took stock of the room. It was small, but it would be interesting to see if we could get away with sex in here. I would bring that up when she came back.
It was a while later when she did and I almost thought she'd left without me, since my keys were in my pocket on her body. But she entered with four pairs of jeans and four shirts, all different sizes. "I figured I'd get them all and try them all so I wouldn't have to keep going out looking like this. No offense." She took off my jeans and gave them back. I didn't put them on right away, though.
"None taken," I replied. "Hey, wanna have sex?"
"What, in here?" she asked. She looked around.
"Okay," she said. She took off her shirt too.
"I just figured that if we can get good exercise, maybe you can lose what little weight you have to get those jeans on better."
"My caring brother, doing every little thing for me," she smiled. "So how do you wanna do it?"
"Whatever's more comfortable for you."
After a moment's hesitation, she braced her hands against the walls on either side of a corner mirror and leaned forward so her ass was facing me. "I don't know how sturdy these walls are, so you'd better not knock them down," she teased.
"No promises." I slid my cock into her vagina and started fucking her. I began with slow rocks back and forth, taking seriously now her warnings about the walls, but after about three minutes of slowly thrusting in and out and seeing the walls stay strong I decided to kick it up a notch. I went in and out a little faster but could see in the mirror my sister's face was still bored. So I picked up a little more speed and umph! and could see her boobs starting to jiggle in response and she became only slightly interested.
The problem with fucking my sister is that ever since her friend had made her a whore, she has had plenty of occasions to fuck. She was introduced by her friend's cousin and shortly afterwards did her friend's dad, has had a couple of male teachers and plenty of upper classmen take her on. The thing is, she doesn't ask nor beg for sex. She IS sex. To be around her is to want to pound her. It's the way she walks and talks and dresses and looks at you that screams "I'm a fertile, young woman, fourteen years of age who is not against sex. Just ask and I'll probably say yes!" But the problem with trying a thousand different foods is that once you find three or four really tasty dishes, the rest seem meh. That's the way it seemed it was going for her. She has had some really spectacular fucking sessions, and this was not one of them. So she was bored. I had to step up the game.
I reached out and took her arms away from the wall and pressed her tits and chest against the mirror. I was careful to angle her forward so her belly didn't get squished. I think the coldness of the mirror sent shivers through her body, though that was not my intention. I intended for her to leave her mark, and I whispered such in her ear. "Now, whenever someone changes in this room, they'll be looking at our love. Each time a little girl tries on a new dress, she'll look at herself through our sex. Each time a hot guy comes to try on a new shirt, he'll look at himself through your body being pressed against this mirror." And as I said that, my fingers found her nipples still pressed to the mirror and started squeezing them. I was still fucking her, and I moved my head to the side of her head and closely whispered "Mirror, mirror, on the wall, who's the sexiest of them all?" She turned her head to meet mine and our lips locked. Our tongues were at war. Each time my cock invaded her body, her tongue invaded my mouth. Each time I pulled a little milk from her boobs her tongue slammed against mine. And I kept fucking her and could see, out of the corner of my eyes, white streams of lactation running down the mirror. We'd have to clean that up. Then I turned her around and leaned her back on the neighboring wall. She was at a slant and I once again slid my cock where every brother's cock belongs and started pummeling away. Our tongues once again met in battle and this time when I milked her, it ran down her body and down her legs.
We kept this up for about two-and-a-half minutes before I finally could hold myself no longer and released all I had into her pregnant pussy. I found myself on the floor, panting, and she was standing there doing the same. Cum was dripping down from her legs and milk was finishing its journey to her feet and finally the floor. We took a minute to catch our breath and then she proceeded to try on the remaining clothes. She eventually settled on one pair of jeans and one shirt, so we returned the rest and picked out additional clothes like the ones she liked and headed home. Oh, and she was back to wearing her jeans she came in with. Apparently they fit better now.