Titty-to-pretty ratio (TPR) is a subjective measure of a female's overall physical
attractiveness, weighted positively by the mass of titties. It is determined by the ratio of sweatermeat relative to facial
attractiveness. A TPR of 10:10 is a perfect female, whereas a 0:10 is a perfect flat-chested female and a 10:0 is a ridiculously endowed
butter face. A TPR threshold is a ratio of personal preference below which titty cannot exceed pretty for the purposes of copulation.