Versatile sex means that someone is open to being both the "top" and the "bottom" during sexual activities. The "top" person is usually the one who does most of the active movements during sex and the "bottom" person is usually the one who receives these movements.
Imagine if you were playing a game of catch with a friend. Sometimes you might want to be the one throwing the ball (the top) and other times you might want to be the one catching the ball (the bottom).
In versatile sex, people enjoy taking turns being the "top" and the "bottom" during sexual activities. They may also enjoy switching things up or trying new positions to keep things fun and enjoyable. It's important to always communicate with your partner and make sure both of you are comfortable and consenting before engaging in any sexual activities.