Eggs on fire -- tucked into lettuce! (6)
I believe the answer is:
coaxes
'eggs on' is the definition.
(to egg on is to encourage or coax)
'fire tucked into lettuce' is the wordplay.
'fire' becomes 'axe' (I've seen this before).
'tucked into' is an insertion indicator.
'lettuce' becomes 'cos' (cos lettuce is a kind of lettuce).
'axe' placed within 'cos' is 'COAXES'.
(Other definitions for coaxes that I've seen before include "Cables" , "Wheedles" .)