I've made one girl squirt and it wasn't piss. She walked me through what to do and it worked every time. I've tried it on other girls since then but no success.

I've witnessed several girls squirt at swing parties including super squirter Cytherea. It probably shot 5 feet across the room all over some fat dude that was sitting on a chair and not even participating. It was probably the funniest thing I've ever seen at a swingers party.