The fluid makes the urethra less acidic and gives the sperm a better shot at surviving the trip from the guy's testicles to the girl's fallopian tubes. There's usually NO sperm in pre-cum fluid.
But, if there are live sperm inside a guy's urethra (because he has ejaculated recently), the pre-cum can "pick up" the leftover sperm on its way through the urethra and out of the penis. If a guy pees after he ejaculates, that would kill leftover sperm.
So, say a guy has sex and cums at 9 p.m. He doesn't go to the bathroom after he has sex. At 10 p.m., he gets another erection and pre-cum fluid is released. That can have live sperm in it. Is it enough sperm to get a girl pregnant? Possible, but not probable.
I think im safe