Funny enough this style of thing comes up a fair bit . Girl tells guy his 8 by is average, she has seen several bigger, even though she has had only a couple of lovers etc. Of course this is terribly umlikely and I thought it may be a deliberate ploy to knock the guy down by showing disrespect for his penis . Two things were then suggested, firstly that calling an 8 by 6 average, is not disrespectfull and second that the girl might not know it isn't average. The first point would make the second moot, so here i am polling it .
We now have a third suggestion from Tjt ,that top 1% might right fully be regarded as average, so for instance a 6' 6" guy might rightly be regarded as average height.