Northerner puts son on bed (4)
I believe the answer is:
scot
'northerner' is the definition.
(I've seen this before)
'son on bed' is the wordplay.
'son' becomes 's'.
'on' says to put letters next to each other.
'bed' becomes 'cot' (cot is a kind of bed**).
's'+'cot'='SCOT'
'puts' is the link.
(Other definitions for scot that I've seen before include "A Caledonian?" , "Tax, Glasgow native" , "Native of country of the UK" , "One from north of the border" , "Glaswegian perhaps" .)