Get down to business and discuss what to have for Christmas? (4,6)
I believe the answer is:
talk turkey
'get down to business' is the definition.
(both can mean to talk frankly)
'discuss what to have for christmas?' is the wordplay.
'discuss' becomes 'talk'.
'what to have for christmas?' becomes 'turkey' (turkey is often eaten on Christmas Day).
'talk'+'turkey'='TALK TURKEY'
'and' is the link.
(Other definitions for talk turkey that I've seen before include "Speak frankly (about the Christmas dinner?)" , "Discuss a matter straightforwardly" , "have a frank discussion" , "(In business) discuss frankly" , "have real discussions" .)