There's a difference between what you see in the pornos and actual squirting. I had a man once who insisted on making me do the porno kind and it's really a widdling fetish, as you say and I was not comfortable AT ALL. If you want your girl to piss at orgasm, put down plastic sheeting first.
A true vaginal squirt is what she is doing already when she coats you. Gushing is involved, sometimes creamy, sometimes clear, depending on the time of month. But it's hardly a fountain, more of a flood. It wouldn't show up in a porno.