It happened by accident, actually. My brother and I were walking home from school and I had to go to the bathroom real, real bad. I mean, really bad. I didn't think I'd make it home. I tried to rush him but Caleb thought it was funny and I'm not allowed to let him walk home alone — otherwise, I would have left him.

We were only a few blocks away when I realized that I wouldn't make it. There's an abandoned house with an overgrown yard we pass so I slipped into the gate.

"Katie! Where are you going?" Caleb yelled before following me in. "Whoa! Creepy. Glad I don't have to mow this lawn."

I ignored him and raced for the house. If the plumbing didn't work, at least I could piss inside.

Caleb grabbed my arm before I could get to the front porch. "You can't go in there!"

"Let go!" I struggled. "Come on, I really have to go!"

"Even so, you can't get in there — the door's nailed shut."

I looked over my shoulder and saw in horror the boards covering the door and windows.

Then it happened. I remember the moment exactly. Caleb was holding my arm still and we were very close, almost touching in fact. I was wearing a knee-length skirt and stockings and a sweater because the day was just a little cool. But the pee that suddenly soaked my panties and flowed down my legs was warm. It drenched my stockings and made a big wet spot on the front of my skirt. I was mortified that Caleb had seen it and that I would have to walk the rest of the way home with my shame cooling in the breeze.

But I was also shaking. Shaking because it was such a release. Such a relief. It felt so good to let go and let everything flow. "Oh God." I moaned.

Caleb looked me up and down. "Did you just piss yourself?" He whispered, so shocked he was almost frighten. I couldn't speak, only nod. "Tell the truth. It felt good, didn't it?"

"I — uh —"

"It did, didn't it?"

Tear fell and I nodded again.

Caleb didn't let me go. With his free hand, he unzipped his pants and pulled out his cock. I was so shocked I couldn't move. "I know it felt good, big sis. It felt like this." He closed his eyes, let his head fall back and a stream of piss poured from his cock to my skirt. The smell of our mixed pee was strong but somehow it didn't make me sick, I just shivered a little more.

After a moment, he'd stopped peeing and I realized that he was rubbing his dick up and down slowly. It was stiff and seeing it made my stomach quiver. I felt like I needed to pee again but not as badly.

We stood in the abandoned yard, surrounded by weeds and tall grass, hidden by the tall fence and my little brother rubbed his dick until his spunk splattered my skirt in the same spot his pee had hit it.

Then he let me go and straightened his clothes. "Will you do this again with me tomorrow?" He stared at me oddly and I found myself nodding before I even knew I was. "Ok. Come on." We walked the rest of the way home in silence. We didn't see any one.

Caleb and I are the youngest two in our family. All three of our elder siblings have gotten married and moved away so it's just us two with mom and dad. We spend a lot of our time together. We're very close.

Maybe too close, I thought as I brushed my teeth before bed. Maybe I should start wearing pajamas to bed instead of an old t-shirt.

A knock on the bathroom door interrupted my thoughts. Before I could answer it, Caleb slipped in and locked the door.

"What are you doing in here?" I whispered, aghast that he would just enter but quivering again too.

"I have to good. I thought you might have to too. Have you gone yet?" I shook my head. "Good. Come here." He started the shower spray, adjusted the temperature, then turned it toward the wall. He reached for my hand and, drawn to him, I stepped into the tub.