How to achieve pressing against invisible wall effect facing camera? (animation) i'm quite new to blender.

I'm making some animations and i would like to reproduce this effect 



Not only for the tongue,any part of the body ( hand/foot/derrière/chest )

To resume ,a character pressing against invisible screen facing the camera with this " collission " effect for any part of the body touching that invisible screen.

(i have not found anything about rigged characters and collisions for animation )
This is not a simulation but a similar effect can be obtained very simply with a shrinkwrap modifier:



Set the modifier to "Project" and "Outside" (if orientation faces the model / normal of it pointing to the monkey).

Axis the one of the glass normal. Direction: positive. Cull face is not needed.

I've added a subdivison after it to curve a bit vertices that are stretched by the glass.