When a guy mimics your movements, he's subtly indicating that he's interested in you. Sitting in the same position as you, making the same hand gestures, and leaning in the same direction are all subtle signs that he's interested. The more you can match his behavior, the more attracted he will be to you. Mirroring is one of the most powerful tools in the arsenal of any good flirt. By copying someone else, even if it's only internally, you're giving them permission to get to know you better. This allows them to see what types of behaviors attract you, which lets them replicate those things. Guys mirror your actions because they want to see where they stand with you. If you make a face or move your body in a certain way, they want to know if you like what they're doing too. This gives them an idea of how you feel about them, which is important because it helps them decide whether or not they want to pursue a relationship with you. If you don't want him to mirror you, then don't mirror him back! While flirting is generally done between two people, sometimes one person will mirror another just for fun.