The vagina will expand. Yes, expand.

No joke here, people. According to Ricciardi, good sex will cause a woman's vagina to lengthen or "expand" during penetration.

"This is simply a result of the vaginal muscles relaxing which means you're doing it right!," she told us. "If you notice her vaginal muscles relaxing as you thrust into her, good job! Just remember, if you've been at it for a bit, you will start to feel them contract which usually means she's about to have an orgasm — an even better sign."

[Photo via @grlwithbangs]

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