1. Once any romantic feelings arise, end it.
Learned from: Chasing Amy (1997)
Complex says: If you keep looking into her eyes and getting lost, it's time to wrap things up. There was an agreement that no romantic feelings would be involved and both parties have to honor that. If you dwell on those feelings, and you let them grow, they're just going to explode in your face.
If you honestly feel the need to tell her about your feelings, and you think it's the real deal, hopefully you won't have as hard as a time as Ben Affleck does in Chasing Amy. Assuming the girl you chose to be your FWB isn't chilling at the opposite end of the Kinsey scale, of course.