Originally Posted by
jraf
While the math may be correct: 4 quickies @ 15 min = 1 hour, the reality is different.
Whatever the length of time you are making a donation for, the donation has to cover for the total time involved in the arrangement. For the men, the total time is as arranged, but for the women they have to account for cleaning up (selves, space) and getting ready for the next appointment.
If you are seeking a situation of maximum efficiency, you'd want to seek out something like a gloryhole.