Measurement method?

TS girl sometimes advertise that she has schlong of 9" or 10" or plus.. how does she measure that? someone says it look like 7 while other says it looks like 10? for example, for baseball team to start the game, by either coin toss or hand grab the baseball bat and climb up to top.. well, my meat.. i can grab it with my both hands and still see little of my shaft and cockhead. does it mean its approx 10 inch?