Very hot farm animal gripping leg (6)
I believe the answer is:
piping
'very hot' is the definition.
(I've seen this before)
'farm animal gripping leg' is the wordplay.
'farm animal' becomes 'pig' (I've seen this before).
'gripping' means one lot of letters goes inside another.
'leg' becomes 'pin' (pin is a kind of leg**).
'pig' going around 'pin' is 'PIPING'.
(Other definitions for piping that I've seen before include "The playing" , "Lengths of tube" , "Tube; very hot" , "Metal or plastic tubing, or trimming on garment" , "Long tubes" .)