It's true that measuring to the bone is the most precise way and it's why those in the PE world use it. However, if you want to measure the way most doctors measure in their studies (so as to properly compare) you will need to stop at the pubic skin and not push to the pubic bone, measuring on top of the penis. The problem with measuring to the skin is that it allows for weight to be a factor (fadpad hides penis), which hardly seems fair, but that is the standard way of measuring. Also, those who see a person's penis are going to judge it's size by what they see, so the measuring to the skin will give one the measurement as to what people judge it to be. It's probably no accident that skinny guys have a reputation of more often having the longer penises, as the fatpad can hide quite a lot. During intercourse perhaps an inbetween length measurement is OK, as the fatpad can be pressed in to some degee. For instance, if one has a 1" fatpad and measures 6.5" to the skin and 7.5" to the bone, then 7" may be about what is actually used during intercourse.