Chloe stole your kwami and promised to return it. And here you get a message from her. That's what it says:
"Marinette~ I told you I'd hand you kwami back, but I didn't said it was free. PS: Waiting in the bathroom))"
Chloe also attached a photo to the message where she is sitting on the toilet without pants and has a huge dick visible. Marinette realizes that she will have to take Chloe's cock in her mouth