It's a common expression used to ask someone if they are thinking about the speaker. It can be used in both romantic and platonic contexts.
Here are some examples of how it can be used:
* Romantic: "Piensas en mí cuando estás lejos?" (Do you think of me when you are away?)
* Platonic: "Piensas en mí para el proyecto?" (Are you thinking of me for the project?)
The phrase is often used in songs, poems, and other romantic expressions. It's a way to express longing, affection, and a desire for connection.