In highschool we had a track competetion up-state and we had to take a 5 hour school bus trip to get there. We made a stop about half way there, and we all bought big drinks with lots of caffeine at the store where we stopped. Bad idea, considering I have the world's smalles bladder. But, when I was having fun with my friends I didn't even think about it. After about an hour of being on the road, I had to pee, but we had at least another hour, maybe two, so I tried not to think about it. After another 15 or 20 minutes, I really had to pee. I tried to cross my legs and chat with my friends, but I could feel it starting to leak out. I was getting desperite, so I went up and asked the bus driver how much longer. He said it would be another hour and I asked if we could have a stop. He said we couldn't stop because we had to be at the competition by noon, and if we stopped we would be late. I sat back down and almost started to cry I had to pee SOOOO BADDD!! I put my hand on my pussy and pressed hard, but it didn't help. I could feel more leaking out. Finally after about 20 minutes of pure agony, I just gave up and pissed myself on purpose. I couldn't help it. It was really embarassing!