I'm not a lady, obviously, so my apologies for replying, but my older FWB, she is in her 50s, she is not a squirter, as much as a gusher. Had her over one time (a few months ago), she was on my bed, she soaked through the comforter, through the sheets, through the whatever the heck you call that thing you put on under the sheet, and actually got the mattress wet. I had to put a hell of a lot of effort into getting the mattress dry and clean. The other stuff went in the washer, but the mattress got pretty danged wet. When she comes over again soon, there will be extra precautions with my bed.
I know a former FWB from about a decade ago was a a prolific squirter, and apparently, they make special blankets with plastic in them, to prevent it from soaking through. When she'd come over, she'd bring her special blanket.