Jan 27, - The vagina is an elastic tube. And it has a muscle that can be relaxed and contracted consciously. A vagina entrance will normally be mostly What is the size of the vagina of a virgin? The average vagina is inches long, but fear not if your guy is hung like a horse. The vagina can expand by percent when sexually aroused, kind of like a balloon. Remember, the vagina was made to birth babies, so it's exceedingly elastic.