Sways to some music with son (5)
I believe the answer is:
rocks
'sways' is the definition.
(I know this)
'some music with son' is the wordplay.
'some music' becomes 'rock' (rock music).
'with' means one lot of letters go next to another.
'son' becomes 's' (genealogical abbreviation for son).
'rock'+'s'='ROCKS'
'to' acts as a link.
(Other definitions for rocks that I've seen before include "Boulders" , "is brilliant" , "Lumps of hard mineral matter" , "Causes shock to; diamonds" , "Excites" .)