When you're aroused enough, the walls and lips of your vagina slowly open up to welcome in whatever it is your partner is offering, and your body quickly puts these movements into the memory bank to use again later. Fortenberry, J. Many others have already inadvertently ruptured their hymens before they ever have sex. Nope, nope. In addition, your vagina will probably temporarily expand or lengthen. Vasilenko, S. Florio Mar 11 After you've decided to start having sex , you'll probably have a whole laundry list of questions about what will be different from now on. And if not: Even how your vagina lubricates itself will change over a period of time. After you've started having sex, though, is a completely different story. Foreplay is anything that leads up to intercourse. After you have sex, your vagina becomes more flexible — your vagina will get more used to penetration, which means sex will get more comfortable for you as time passes. That's all?! The truth is, even if it's not your partner's first time, it's their first time with YOU. You can lose it again. If you're thinking of having sex or if you've already started, you'll want to start talking to your doctor about it. Their size will fluctuate with your arousal meaning, they will not be any bigger when you're paying your taxes or waiting in line at the grocery store.