Some years ago I was at a lecture which involved a discussion group around a fountain that played in time to music. After about 5 minutes I was almost holding myself to stop myself from having a pee accident. I excused myself and was the only male among a group of five or six women who rushed to the toilets.
On the way back several people said they "only just made it" and two of us admitted to having soggy underwear. This was a little while before I became incontinent but I had been very close to a "fully blown" accident.
This thread was prompted by the "How often do you pee" thread on the diaper forum. I am aware of other things that trigger a similar urgent need to "go" but won't list my danger points here.
Why does this happen and what else can have the same effect?