Quoted from sslakkerr:I'd prefer to make it activate/deactivate automatically, but not really sure what a good trigger for that would be since it would need to be something only on during a game...
I soldered a wire to the capacitive sensor on Grogus head and placed the end of the wire near the left flipper button (similar to the video below). That way it is only activated during play. I did place it a bit differently though, so that it is not registering touch all the time. Makes Grogu move a bit more randomly and saves battery (as I also still use the battery box).
Big thanks to AceJedi and Driftin8ez!