Shouts from son twice drinking best (7)
I believe the answer is:
'shouts' is the definition.
(I know this)
'son twice drinking best' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'twice' indicates the doubling of some letters.
'drinking' indicates putting letters inside.
'best' becomes 'cream' (as in 'the cream of the crop').
's' doubled is 'ss'.
'ss' enclosing 'cream' is 'SCREAMS'.
'from' is the link.
(Other definitions for screams that I've seen before include "Yells" , "Shouts" , "Shrill cries" .)