After a very long hold lasting 5 and a half hours (you can read it > here <)  I finally got my relief. I had completely emptied my bladder prior to starting and I had changed into a pair of black leggings with nothing underneath. The filling up and holding was really fun, many thanks to everyone who encouraged me and took part in the live action thread! I became more and more desperate and at just before 10:30 I leaked, a spurt of pee soaking into my leggings. It was time to let go properl