Stepsister Couldn't Hold It

[wetwulf 3,324]

This is a long one, but a good one. True story, with a little bit of creative liberty.

When I was about sixteen, I was riding in the back of my father's pickup with my older stepsister, who was nineteen. We were coming back from a swimming trip to a nearby lake. I noticed that my stepsister was holding the crotch of her dark blue jeans shorts and wincing a little. She was wearing a black one-piece bathing suit underneath and as she pressed on her crotch, the top tightened a little, showing off her nice breasts.

"I've got to pee," she finally said. "How much farther to the house?" I was only visiting my father for the summer and did not know much about the area.

"Not sure," I answered. She leaned forward and her face contorted, expressing her growing discomfort.

"Oh, God, I'm about to explode. This hurts so much. I don't know if I can make it." I thought for a second for a solution. As she squirmed again, her hand moved a little and I noticed that her jeans were a little damp.

"Did you pee in your shorts?" I asked. She glanced down to see the dampness and chuckled.

"No, that's just from my bathing suit. I guess it's still pretty wet and it soaked through my shorts. Oh, God." She clenched her teeth and leaned forward again.

Finally, the light bulb went on in my head. "Well, if your bathing suit is still wet, why don't you just take your shorts off and go. It's a black bathing suit, anyway, so it's not like you'll ruin it. You can dry yourself off with a towel." I waited for her to give me a look of disgust, or to bang on the truck window and tell my dad that his son was a pervert.

"I think I might have to," she answered, quicker than I thought she would. "I'm already leaking. I'll just pee enough to take the pressure off and finish when we get home." She quickly tugged down her shorts without unbuttoning them and, trying her best to keep her legs tight together, grabbed the thick beach towel next to her. "I'm going to sit on this so I don't flood the back of your dad's truck." Still keeping her legs together, she lifted her bottom and slid the towel under her. I saw a slight trickle drip from her bottom as she lifted and this prompted her to flop back down quickly. "Okay, here goes."

I waited for her to tell me to look away, but in her desperation she must not have cared. Almost instantly, I could see a glistening begin from between her legs, which she kept together. This amazed me as the stream began to force its way through the crack between her legs and gently caress the tops of her thighs. It pooled there very briefly until it slowly crept its way down between the groove to disappear into the cloth of the towel. She also seemed to enjoy this as she closed her eyes and began to breathe a little harder.

"Oh, God," she moaned. "This feels so nice. Oh, I can't stop. I might as well finish." She opened her legs a little and let go completely, allowing the stream to spray through her bathing suit and into the towel. The distance was not much, but enough to travel a little ways across the towel to leave behind several damp spots.

As I continued to watch, I felt my own bladder announcing its need. We were probably getting close to the house, but I did not care. As if trying out a different position, she leaned forward so that the stream would fall directly from her crotch to the towel. The sight of this sent my bladder and my senses into overdrive. Without saying anything to her, I just let go in my swimming trunks. I had been in the sun long enough for them to dry, so the new wetness felt so amazing as it filled the front of my shorts instantly and dripped gently down my balls and to the crack of my butt.

All this time, I did not take my eyes from her wetting. It seemed to go on forever, although it was now down to just a steady glistening. She was still not paying attention to me and this added to my excitement as I gently continued to pee my shorts in secret. Finally, as her stream ended, so did mine.

My stepsister dabbed at her crotch with the towel and then pulled her shorts back on. She looked at her shorts and seemed to feel confident that the dampness that was there before would divert any suspicion. My trunks were solid black and it was my hope that any wetness would be shrugged off as lake water.

We didn't talk about the incident when we returned home and I never told her about my wetting. But there were a few more instances of her desperation that I may share later.