IT'S A NORMAL BIOLOGICAL FUNCTION OF THE FEMALE BODY FOR GOD'S SAKE.
Some girls do this more copiously than others, that's all. It's just like some girls ejaculate big time when they orgasm, while others don't (check out some of the vids on the ALS Scan site if you don't believe).
Haven't any of you gone down south on your partner for prolonged amounts of time and come back up for air (so to speak) with a fair amount of this on you, even just a little bit of it??? If not I suggest perhaps you are not trying hard enough while you are down there. Personally, I really enjoy going down and making a girl cum with just the use of my mouth
and so far they've all leaked this type of fluid out (both before and while cumming) in varying degrees of volume and appearance... not to mention taste