Tongue Out

Visibility / Keyform Value 0 0.01 1
Default Tongue 100% 0% 100%
"Out" Tongue 0% 100% 100%
Tongue status Stay in mouth Start to get out Fully out

Tongue Out needs a separate XY deformer, that is influenced by any mouth surface deformations, such as Mouth X out.

Things need to get in consideration when rigging tongue out:

Mouth Form
Mouth Open Y
Mouth X
Cheek Puff

And any other vbridger parameter that might get involved, though tongue out unlikely shows itself by accident during face tracking.