Neck displayed by low cape: button it all round (6)
I believe the answer is:
smooch
'neck' is the definition.
(smooching is a kind of necking)
'low cape button it all round' is the wordplay.
'low' becomes 'moo' (both can mean to make the noise of a cow).
'cape' becomes 'c' (abbreviation used on maps).
'button it' becomes 'sh'.
'all round' is an insertion indicator.
'moo'+'c'='mooc'
'mooc' placed inside 'sh' is 'SMOOCH'.
'displayed by' is the link.
(Other definitions for smooch that I've seen before include "neck" , "Dance slowly while in an embrace - kiss - pet" , "Snuggle" , "Canoodle" , "Kiss and caress slangily" .)