Both the anterior and the posterior fornix are part of the “ring” around the cervix and are reported to yield similar sensations. My wife is very passionate (yay!), but sadly, as a result, not really into differentiating between the various spots. When I ask “which feels better?” she usually indicates that it’s all wonderful and for me to please pick one and do it rather than teasing her by messing around with each one for a few seconds. She does say that they both feel very similar though.
The posterior fornix is rather deep and, in many cases, hard to reach for the non-enlightened (those who do not believe in PE). This area is much easier to stimulate through the “back-door” and is often done so during anal sex, it seems, which is probably accounts for the fact that girls who like anal sex REALLY like anal sex.
The anterior fornix is easier to reach in positions that channel the penis to the right spot without slamming into the cervix. The anterior fornix is the one reason I would really like to have one of those banana shaped penises at times. The anterior fornix can often be reached with the fingers.
That’s what I know.
Dr. Lin is a quack. He picks what scientific knowledge is useful to support the sale of his products and leaves other stuff behind. Whether or not he is an actual Chinese health care practitioner or simply using the Lin surname to tap into markets that think Chinese medicine will do neat stuff that western medicine will not (which is true in some cases, btw), I do not know. It seems like if it was a Chinese-run site, they would hire someone to clean up the wording of the site… who knows? However, I can tell you that the site does model many Chinese business practices that will site all sorts of spurious and incompletely reported research in order to sell their products.
The first Chinese physician to figure out the whole penile lengthening surgery in China subsequently went around telling everybody that Chinese men had small penises, that a large penis was absolutely necessary in order for one to get married, and that average penis length was 8 inches. Chinese people flocked to Wuhan, his city of practice, and he got rich. He claimed girth was not at all important, presumably because he did not offer any girth enhancement services.