It sometimes just happens when people are experiencing pleasure or stimulation that they involuntarily pee themselves to some extent... what you're describing sounds a bit more like ejaculation fluid (clear, coming out in 'sprays') which while it might contain some urine, isn't thought to be the same thing. Some people 'squirt' it during sexual intimacy and it is often but not always associated with pleasure and orgasm.
It isn't understood as well as it should be for people with vulvas. In either case it isn't really anything to worry about, however it sounds like it would be a good idea to talk to your girlfriend about it as *she* can tell you far more about how it feels and what it means for her.
"In between two tall mountains there's a place they call lonesome.
Don't see why they call it lonesome.
I'm never lonesome when I go there." Connie Converse - Talkin' Like You