While I do believe that most girls in squirting fetish pornos are just pissing (since, like I said, it doesn't seem possible to do on command), I know that what comes out of me is not pee. I live my life perpetually suffering between either mild dehydration or a UTI, meaning that my piss is (ab)normally cloudy, stinky, and dark. The stuff that comes out of me when I squirt doesn't smell like that, and it dries white on my sheets.

So where is this stuff coming from then? No one knows for certain, but the likely answer is the Skene's gland, which is located on the upper wall of the vagina, around the lower end of the urethra, and is said to also be the biological mechanism behind G-spot orgasms. It drains near the urethral opening.