Sings something poetic in sly fashion (6)
I believe the answer is:
yodels
'sings' is the definition.
(yodeling is a kind of singing)
'something poetic in sly fashion' is the wordplay.
'something poetic' becomes 'ode' (type of poem).
'in' indicates putting letters inside.
'fashion' indicates an anagram.
'sly' is an anagram of 'yls'.
'ode' placed into 'yls' is 'YODELS'.
(Other definitions for yodels that I've seen before include "Sings in manner of Swiss mountain dwellers" , "Sings like a Tyrolean on a mountain-top" , "Sings like Swiss mountain dwellers" , "Sings Alpine-style" , "Sly ode sings in the Tyrol" .)