Not neccesarily bullshit. It's a mixture of urine and vaginal secretions, but if the amount is really large, like more than 3 or 4 oz, it's more pee than vaginal fluid.
I think the "squirter" stuff originated fromt the fact that women, for anatomical reasons, are more likely to involuntarily lose bladder control when the diaphram and/or pelvic area is spasmodically contracting, like during hard laughter or orgasm. A chick laughs hard, pees a little, a chick cums hard, and pees a little. Women's PH level is different so I suspect it's why our urine tends to have less of that ammonia smell than dudes, then mix it with vaginal fluid and you get little or no pee smell at all. When we learned that really cutting loose with the pee added to the fake orgasm performance suddenly you hear about "squirters" all over the fucking place.
To male friends I usually can convince them of what really happening by asking just one question: Where else could all fluid come from other than the bladder?