phone butter
The buildup of food, spit, and other nasty substances in the phone mouth-piece of your mouth breathing coworkers.
Jim's phone butter had a chunk of oatmeal in it!
Butter phone
When your phone is impossible to hold, as if it is greased up with butter
Guy: Dangit! I dropped my phone again.
Girl: You've got a bad case of butter phone
Girl: You've got a bad case of butter phone