Inseam [of your pants] is shorter than pubic bone height.
Here is the Rivendell Bicycle Works method of measuring pubic bone height.
“a. Stand in bare feet on a hard floor.
b. Put your feet 10 inches apart.
c. Hook the edge of a metal metric tape over a thin edge—two rulers, or a thin hardcover book.
d. Pull the tape up hard against your pubic bone. We tell folks, “Try to lift yourself off the ground
e. Have a friend take reading as you do this.
Do this twice, thrice, or a hundred times. As long as the tape is straight and the guy reading the number knows how to read a tape, you should record the highest of all the readings you get. Why not the average? Because you’ll never pull past the bone, so you can’t get a reading that’s too high.”
http://www.rivbike.com/article/bike_fit/pbh_and_how_to_measure_it