As a first year medical student, I am learning an incredible amount of information about the human body. This kind of medical knowledge has the potential to dispel many popular myths and rumors. I do realize that the topic of penis size/how much feeling is in the vagina/etc. has been covered 11ty billion times in the past; however, I thought that it might be helpful to shed more light on the subject, via anatomy. That being said, the main point is that size (length) does not matter (except in extreme cases, e.g. a penis that is 3+ standard deviations shorter than the mean). Unfortunately, due to the huge amount of human variation, the consensus on "average" penis size is continually changing. To approach this issue from a more objective point, we should look at why penis size would matter (to limit the length of the discussion, we should limit the context to heterosexual intercourse). Does having a longer penis make the woman feel better? NO! If any woman truly believes that having an 8" long penis feels better than a 5" long one, then it is all in her head. Why? Many of you may have probably heard that only a small portion of the vagina is actually sensitive to touch/feeling. I had, as well, but, until now, was slightly skeptical. This is completely true, and backed up by anatomical facts. To understand this better, everyone should remember that our nervous system has 2 "systems" - autonomic and somatic. The autonomic nervous system (ANS) is involuntary. A person cannot control what goes through the nerve fibers of the ANS. The somatic system is voluntary and sensory. For example, if you touch a hot surface and you feel pain - that is from somatic nerve fibers. Now, with that out of the way, take a look at this picture. See all those nerves running everywhere? They are almost all part of the autonomic nervous system. The only nerves that are part of the somatic system (i.e. the only ones that provide feeling) are the ones at the bottom (branches of the pudendal nerve). These nerves are only present in the lower one-fifth to one-fourth of the vagina. The clitoris has its own set of nerves, which are branches of the ilioinguinal, genitofemoral, and perineal nerves, and are not pictured above. How long is the average vagina? Again, there is no scientific consensus due to the large amount of variation, but most of the estimates I have seen vary from 4-7 inches. Of course, some penises are longer than this and yet are able to fit inside. How is that possible? Directly behind the external ostium of the uterus (where it meets the vagina), there is a pouch called the posterior vaginal fornix. This space accomodates the erect penis during intercourse. It is not normally included in the calculated length of the vagina; it is illustrated in the following picture. Anyway, that is just a sidenote. Again, the point is that one-fifth to one-fourth of the length of any vagina is really not that much. So, ladies, that's the only part that gives you feeling; and guys, remember that it's not necessarily how big it is, it's how you use it. As far as G-spot stimulation is concerned, it is only 2-3" deep on the anterior internal surface of the vagina, and stimulation by the penis is usually not effective (this info is from Zemo's Vaginarium FAQ). Besides, that spot and its stimulation is not covered in my anatomy books. I hope that this has been helpful. I am only a lowly medical student, so forgive me if I have made any mistakes in conveying this information. I added the SNWS warning to protect anyone who may work for someone who does not like anatomical pictures.