It is amazing how we go over these issues time and time again (even on Christmas morning, while I am up early, sipping coffee, waiting for my grandkids and wife to awake). Accurate penis dimensions as representative of the entire male population, races, and even LPSG members are as elusive as a unicorn sighting.
To be representative thousands if not millions of all types and races of men must be randomly measured as they squeak out on the spot a hard on: an almost impossible survey task to arrange. A six inch girth is clearly, based upon some limited surveys which most of you have read, in the 2.5 standard deviations over normal size as stated above (4.67 to 4.97 inches) given a SD of 0.55 inches ( even this too may not be representative) and thus you are larger than 99% of those measured in that survey.
The problem is that it presumes penile length and girth follows exactly a normal distribution; it doesn't like most things in life. Just like men's heights where the mean height may be 5 foot 10 based upon a randomized survey, there may be more guys who are 6 feet five than six feet two inches. If it was a perfectly normal distribution there would much less men at six feet five than six feet two but this may or may not be actually true, and I know it isn't. The same with penis length and girth which, frankly, next to your eyeballs are perhaps the least variable sized organ in the male human body according to anatomists. Woman's breasts sizes are quite variable in comparison.
Another big issue is how to measure girth and length which has never been really standardized. I can't measure my erect cock with a straight ruler because it bends up and curves at a 30 degree angle. With a shoe lace over the dorsal skin and then taking that string over a fabric tape or straight ruler it may measure from 8.4- 9.0 inches: I give that range because erect penis girth and length is also dependent on a variety of factors and is not set in "stone": medications ( I have to use the sex pills at my age), blood glucose, blood pressure, temperature, the mood I am in, and the last time I had sex, to name just a few. So anyone stating their girth or length using but one three significant digit inch or cm figure I just laugh at. I also have a thick penis at the base, perhaps as big as eight inches when I use a string and ruler or fabric tape ( Note a thick fabric tape may have some issues with inside and outside diameters if the penis is not a straight cylinder in shape). See my gallery. But the girth behind my glans and at my mid-shaft are smaller to be sure.
But other guys are different; most "measurement theory" now subscribes to measuring the base, midshaft, glans and averaging the results. As far as pleasing a woman though ( and my issue is that I am very big according to my wife who has had hundreds of men before me but now is menopausal and so gets much more pain than before), remember that the vagina grips like any hand so it can accomodate all but the smallest or largest girths and gets pleasure only if the woman desires pleasure. Size really does not matter since her pleasuring ( if she is not menopausal and can self-lubricate) really has nothing to do with your size but all sorts of other factors she controls in her mind and you may or not influence ( e.g, how wonderful was your time at the dinner and movie last night, how romantic you are, how good she feels, how sexy she feels, how you smell and look).
Certainly most of you younger guys must know this by now.