After I read this I spit my gum out

I always snap my gum when I have it, it's almost an unconscience nervous thing I do like pick at my fingernails. But my jaws get tired quick and I spit it out. If she's like me and you've only mentioned it once she's probably forgetting it because she's concentrating on work and doing it unconsciencously. I'd try Tuckerville's suggestion so she thinks of it.

Then throw a cushball/stressball at her if she forgets Good luck!