A few years ago our mom took Lily and I shopping around Christmas time. We weren't allowed to buy anything since it was close to Christmas ("Ask Santa." hehe.) But we got to look around and get ideas for what we wanted. Anyway, about an hour into our shopping trip I felt the need to pee. I headed for the bathrooms only to find a REALLY long line. I decided to continue shopping and try again later. About 30 minutes later I was trying on some clothes in a large family/handicap accesible dressing room, I used the bigger one so I could take Lily in with me and she wouldn't have to sit outside the room being bored. I was in between outfits wearing a training bra and panties when all of a sudden I felt like someone was pressing on my bladder really hard. I had to go pee sooo badly; the kind of emergency where even the most modest person has to at least cross her legs to stem that incredible urge down there. The store I was in didn't have a bathroom and the closest one I knew of was quite a ways away.
When Lily saw my reaction to the sudden emergency she asked what was wrong. I told her my problem and she suggested we try to make it to the bathroom. I told her that by the time I got re-dressed I'd never make it but she insisted that we try anyway. I again told her that I'd never make it, that it was going to come out NOW so I quickly jumped over to an empty corner, pulled my panties down and squatted. I peed for about 30 seconds and left a medium sized puddle/wet spot on the carpet. Lily giggled the whole time. When I was finished I quickly re-dressed and we left that store. Lily also had to pee but is shy about public restrooms and thought she could hold it until we got home. She almost made it. About 2 minutes from home she flooded, and I do mean flooded, her pants. I don't know if any of you have ever witnessed someone peeing when they've held it to the bursting point, but the look of relief on her face while she was going and even afterwords made me wish it was happening to me so I could feel what she felt.