question about mental bond

[Grey]

so the description for mental bond says a mental and physical bond (there's a typo of the word 'physical' in the shop description - just thought i'd also mention that).

can the mental bond be simply a mental bond without the sharing of pain?
at the same time, it says they share emotions but is it only just emotions or can it include thoughts/instincts? like the whole "are you thinking what i'm thinking?" kind of bond?