JM,
This is a hard question for me to answer. It has been my experience, and I know from the posts I’ve read that I’m not alone in this experience, that women have a very poor judgement of what the size of a penis is. They’re horrible at it. I think that most women have an image of a penis in their mind that is larger than most penises. I’ve seen too many women look at a picture or watch a porn video with me, that has a man with a seven or eight inch penis, only to have her say it doesn’t look big at all. Meanwhile, I’m crapping in my pants and getting all notions of having sex (this is before I was married) with those who did this out of my head. If they think an 8 inch penis looks average, I had no interest in finding out what they thought about my 5.75 inches.
In fact, if my wife didn’t know what my penis looked like when I’m having a thin phase (I gain and lose weight like crazy), I wouldn’t let her see my penis right now. I’m at the peak of a fat phase, and my NBEL is a full 1.25” smaller than what it was when I was at the peak of my thin phase. That 1.25” makes a big difference not only to the way my penis looks, but to the way I feel about it.
Hmm… I think I’m going to go on a diet.
Anyway, to answer your question. I think most women would say something in the range of 6.5” in length and 5.0-5.5” in girth with their mouth, and have the picture of a 8” X 5.5” in their mind. But there may be a difference between what I think and what is true.
"Only enemies speak the truth; friends and lovers lie endlessly, caught in the web of duty". -Roland, in Stephen King's The Last Gunslinger