In a girl's embrace, he flails! (6)
I believe the answer is:
lashes
'flails' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Maybe you can see a link between them that I can't see?
'in a girl's embrace he' is the wordplay.
'in' means one lot of letters goes inside another.
'a girl's embrace' becomes 'lass' (I can't justify this - if you can you should give a lot more credence to this answer).
'lass' placed around 'he' is 'LASHES'.
Can you help me to learn more?
(Other definitions for lashes that I've seen before include "Eye hairs" , "on the lid" , "Punitive strokes of a whip" , "Rushes" , "Strikes with a whip" .)