Actually, the right way to measure girth is take the side to side measurement, say 1.5" and multiply that by pi or 3.14=4.71.
I am 2.2" across exactly so that is 6.9" which is thicker than most. Being 6'2" and big everywhere, my girlfriends seem to like that I am 8x6.9. Most favor reverse cowgirl that way they can take as much as they want or all of it.