Face: Weeping is a Sticker that you can use you customise the communication wheel of your avatar. You can make your Ninjala character use the Sticker in battle by pressing up on the d-pad and selecting it from the wheel.
To adjust which Stickers you have available in battle, you can change the communications wheel selected by going into the Closet and then the Communications menu.
‘Face: Weeping’ Official Description
“Sticker that is crying. For when you are sad, down, or lonely. If tears well up for no reason, then maybe you should see an eye doctor.”
‘Face: Weeping’ Appearance
A sullen yellow face appears, looking down with a tear in its eye when you select Face: Weeping from the communications wheel.