Six French doctors took a squinting look at whether and how seven women squirt. The doctors published this study explaining, to some extent, what they did and why they did it:
“Nature and Origin of ‘Squirting’ in Female Sexuality,” Samuel Salama, Florence Boitrelle, Amélie Gauquelin, Lydia Malagrida, Nicolas Thiounn, and Pierre Desvaux, Journal of Sexual Medicine, epub December 24, 2014. (Thanks to investigator Ivan Oransky for bringing this to our attention.) The authors, at several institutions in France, write:
“METHODS: Seven women, without gynecologic abnormalities and who reported recurrent and massive fluid emission during sexual stimulation, underwent provoked sexual arousal. Pelvic ultrasound scans were performed after voluntary urination (US1), and during sexual stimulation just before (US2) and after (US3) squirting. Urea, creatinine, uric acid, and prostatic-specific antigen (PSA) concentrations were assessed in urinary samples before sexual stimulation (BSU) and after squirting (ASU), and squirting sample itself (S).
“CONCLUSIONS: The present data based on ultrasonographic bladder monitoring and biochemical analyses indicate that squirting is essentially the involuntary emission of urine during sexual activity, although a marginal contribution of prostatic secretions to the emitted fluid often exists.”
Here’s further detail from the study:
UPDATE (also December 24, 2014): An earlier, related study, with a self-explanatory title:
“Endogenous female prostate-specific antigen from female ejaculate may confound the use of prostate-specific antigen as a biomarker of exposure to semen,” Gwinyai Masukume, Contraception, vol. 89, no. 1, 2014, pp. 68-69.
BONUS (possibly unrelated): A video of how to make a “high power super soaker”: