either she was telling a joke about you or something dirty ( like "imagine him naked... blablabla") or she was making fun of you (which i hope is not this option because you seem like a nice guy and it would be disrespectful from her).
If she does it repeatedly, maybe you should talk to her about it or just let her go.
Good luck :)
She's probably just trying to get your attention. If she likes you she wants to make sure your eyes are on her twenty four seven. For all i know she could be saying nothing to her friend, just tricking you. If you like her back, and are feeling flirty try doing the same to her, she notice that you are responding.
Sounds like she's making fun of you. Just ignore her and find someone else to crush on. If she is playing mind games with you, she also isn't worth it. I hate when women do that to people they like. It just sends mixed signals.
She probably likes you and was just trying to get your attention. Whatever she told her friend couldn't anything bad about you.
Maybe she did it randomly
You can also add your opinion below!
Most Helpful Opinions