The 'D' scale rates a woman on her dirtyness using a scale of 1 to 10. A rating of D1 is extreme frigidity whereas a D10 is positively prolapsed - a good score is somewhere around a D6.
What do you reckon that woman is on the 'D' Scale? A woman who prefers missionary, no oral is a D3, D4 likes receiving oral whereas a D5 likes receiving and giving. A D6 likes a finger up the bumhole and a d6/7 likes anal. A D8 is quite rare and perhaps likes two's up and a D9/D10 has had many years of being battered up the rear.
The D scale can be further refined with the addition of 'L' for looks and 'B' for body so, I'll be keeping my eyes out for a D6L7B6 thanks very much....
The D scale allows you to rate women say when standing in a queue for a sandwich with your mates..