The more foreplay you give, the more a vagina can take as it opens up more and elongates.
This is indeed true for every woman. The more stimulation you give, the more the vagina will elongate.
The average vagina can elongate to accommodate roughly 7". While it's true it fits a baby coming out, you have to remember, that's only because of special hormones that are only present during the labor process to actually allow it to expand that much. Any other time, it's not gonna happen, no matter how excited she gets.
I would think that the vagina is like *****, various sizes. I have read that a woman's vagina can increase in size as much as 3 times with the proper excitement, from personal experience, and proper treatment, I think it will get larger or maybe I have a misconception of what 3 times is.
My wife has had a 10 inch, but surely could not take it all. I believe she did get about 9 or so, but do not feel she could handle any more....it hits her womb
Put it this way: it can take a baby coming the other way.