Men always think length is the important thing when talking about size,but as the average vagina is only around 4-5 inches what would you do with the rest of 13.5 inches? It is thought the vagina can stretch to accomodate around 8-9 inches comfortably. Girth is the far more important measurement in my opinion,afterall you could have 13.5 inches length and only 2 inches girth which would not be much use at all to anyone.lol.