If you vent the room you're in of the vapour, you're not being constantly bombarded by its smell/taste, which helps cleanse the palate faster. Coffee certainly helps, as does eating/chewing/smelling anything that isn't similar to the flavour you're vaping or the next flavour you're about to vape (like coffee). How do you do black coffee? I can't xD. All vape tongue really is is your body becoming acclimated to that smell/taste, becoming your body's new natural default state. It happens with food (if you eat the same thing for a long time) and i got this a lot when I used to pack good hookah bowls that would last for hours.
I'm one of those .....head cloudchasers, so my batteries never last long enough for me to get vape tongue, and I can't chain vape or else my mod (hello copper) gets pretty warm.
Good luck!