This is a story that happened to me and my twin sister age 13. We both were 5'4" tall, blue eyes, light skin color with dark brown hair (her's long and mine short). Our mother took us on a bus ride to the boardwalk. We entered the bus from the rear side door. It was very crowded so we had to stand near a pole. The next stop more people got on so now my sister and I had to squeeze together. She was in front of me hugging the pole and I was behind her. The position was all innocent till she reached around to scratch her butt.

As she did this, the back of her hand kept rubbing up against my dick. She didn't do it long but it was enough to get my dick growing. I tried to forget what happened but the bumping caused by the bus made my boner keep hitting my sister's ass. She was wearing a short wavy skirt with tight cotton white panties. She had a very nice little ass.

"Jack I'mma kill you if that's your penis".

"It is I'm sorry...not my fault".

"Just get it away from me".

I pushed my hips back to keep from poking her. The more I thought about poking her the harder I got but the more pain I received. My khaki shorts did not stretch enough to accommodate my 6 inches long. After a while my back started to cramp, and my dick was hurting so I looked around, with so many people around no one could see. I unzipped my shorts, pulled my dick out and slowly stood up straight. I carefully guided my hard dick between her legs, sliding it across her panties. She jumped a little, causing her legs to close around my dick.

"Jack what the hell you doing"?

Now my dick is locked between her legs, firmly snugged up against her pussy. I began to slightly move my hips back and forth. I saw her about to turn her head, probably to yell at me. I thrusted and she let out a moan. She then turned away from me and started to move her hips back and forth. She reached down and grabbed the head of my dick. Her small fingers gripped tightly around it...felt great. She then pulled my dick upward. The hotness coming through her panties was intense. I could feel my cock sliding over her pussy lips and clit. She started to get damp between her legs.

I wanted to feel skin on skin, so I put my hands under her skirt on each side and slid my thumbs in her panties. Then I slowly started sliding her panties down, she stopped her movement..

"We can't Jack" she pleaded.

"C'mon, just for a little bit".

I continued to rock my hips back and forth.

"Please Jack stop" she whispered.

I then took my hands and placed them over her breast and gently massaged them. I lightly pinched her nipples and kisses her neck.

"Mmm Jack".

After a few minutes of pleasuring her, she released my cock and slid her panties the rest of the way down. My cock smacked right up between her lips. My god, the heat and wetness from her pussy was unbelievable. She placed her fingers under my dick head to keep it in place then resumed sliding her pussy over it. She took longer grinds and I felt my head slide over her pussy opening. I kept massaging her breast and kissing her neck.

I couldn't believe what she was doing...let alone myself. She began to pick up speed, I could hear her panting and that is when the head of my dick popped right into her tight wet hole. She grabbed the pole with two hands, held her breath and froze.

"Ow Jack"!

"Shh...people will see"!

I looked around and to my surprise no one had noticed us. Mom was talking to a couple other ladies.

My god her pussy was so tight, her pussy had a death grip on the head. I didn't dare to move, I thought I hurt her. But then she started to push back on my dick. Was she really doing this...?

After a few thrust by her, I slid a little more in. I couldn't believe it. She just kept pushing back on me and the more she pushed, the more my dick went in. Every time it did, she would stop, it had to hurt being so tight. Her pussy was so hot, wet and tight. It also felt like her pussy was trying to milk me. It was absolutely an amazing feeling.

She didn't have far to go, just two more inches. I grabbed her hips and I started to slide out and back in again. Each time I went in, I added pressure. It took just four more strokes to get myself all the way in her.

I started to slide out then thrusted back in. She was panting like crazy and had a kung fu grip on the pole. I couldn't be taking much more, the pressure was starting to build in my nuts. I suddenly felt her pussy clamp down on my dick and she began to shake. Then her pussy started to pulsate, her orgasm was very intense I had to put my hand over her mouth to keep her from screaming.

"MMMMMmmmm" she moaned.

"Shhhhhh"!

After a few more thrust I couldn't hold back any longer. I thrusted in, balls deep and exploded into my sister. I felt like I would never stop cumming, just squirt after squirt. What made it even more intense, was that she orgasmed again! She bit down on my hand and her pussy milked my cock for every last drop, was an incredible feeling. After our orgasms subsided, she nor I could move, after a minute or two, my dick slid out.

We heard our mother say "get ready, our stop is next". We both rushed to put our "stuff" away. I saw that our juices were dripping out of her pussy.

"Whew! No blood, I didn't hurt her." I thought to myself.

But I felt sorry for my sister, she had to walk all day with cum soaked panties. Later that night I told her I was sorry for what happened.

"Sorry Crystal, I don't know what came over me...I mean you are a gorgeous girl, just was wrong and please don't hate me"

She kissed me on my lips.

"Don't be sorry, I'm not. And you're very handsome and I love you".

"I love you too but I'm worried that you are pregnant".

"I can't be...my period hasn't came yet"

She walked away then turned around.

"I'll see you in bed tonight".

Then winked and continued walking away. I got an instant chubby.