missed home plate
 

Runner slides home but does not touch home plate.
What are umpires proper mechanic?
Can the defense make a life ball appeal and just touch home plate?
Or must the defensive player tag the runner?

Similar to your post about runner missing 1B.

Proper mechanic for the umpire is to delay a beat then signal safe. A runner passing a base is assumed to have touched the base until properly appealed.