Oh, very interesting. I have never done the calculation.
Hmmm.... couldn't we get an electronic counter which measures both number and penetrated body part. That way we can keep a permanent database and Igor might get the opportunity of a fuck (or blow job or buggery) without the fear of data collection errors.Basically you got to define a function that approximate the behaviour from a number of given temporal points (X axis) and intensity/effects (Y axis). Since you want to calculate the number of fucks you are looking at the area described by your function, namely to integrate the approximation equation from the moment x=zero of interogation to the x=final of the torture session. Of course, assuming there's no points of discountinuity, like when the subject bites the penis and the fucking go into hiatus.