"Sir Isaac Newtons himself, who cou'd measure the courses of the Planets, and weigh the Earth as in a pair of scales, even he had not Algebra enough to reduce that amiable Part of our species [women] to a just equation: and they are the only heavenly bodies, whose orbits are yet uncertain." --David Hume (in a letter dated 1751)
My dear sir, while I've no doubt you are on the precipice of producing the "just equation" Hume refers to -- and many more pertaining to women and sex, I'm sure -- your original equation remains flawed. My reductio necessarily remains intact because the equation will always produce a negative value for any individual with a sufficiently low number of partners with low rod-strokes-to-milking-completion values.
(Example: Supposing a woman has had a single past partner, the rod-strokes-to-milking-completion value is set at 3 as in my original example, and this previous partner thrust into the woman at least once, the equation still generates a negative value, an impossibility given the circumstances.)
I suspect we will be compelled to utilize the notion of a function to capture the essence of what we're after here.
Respectfully Yours
hs