Measure of how often you get laid, the lay to day ratio is an average measure of how often you get laid. The formula is simply times laid/number of days. The threshold for being a pimp/slut is not clearly defined.
If you get laid every 5 days, your lay-to-day ratio is 1/5 = .2, if you get laid 13 times a year it is 13/365.
Usage: Man, my lay-to-day sucks right now!!