Okay kiddo, when grown-ups have a certain kind of thought or mental image that makes them feel nice and tingly in a way that's related to love or sex, we call it an erotic fantasy. These thoughts can be different for different people and could include imagining being in a romantic or sexual situation with someone they like, or maybe even someone they don't know too well.
These thoughts can make grown-ups feel excited or turned on, but it's important to remember that erotic fantasies are only supposed to be in our heads and not acted out in real life. It's like pretending in a game, but a game only grown-ups understand!
It's okay to have these thoughts and feelings, but it's important to always respect people's boundaries and consent in real life. And just like we don't talk about some things in public, we don't talk about erotic fantasies with everyone. But if you ever have any questions or feel confused about something, it's always good to talk to a trusted grown-up or a professional.