Heart-throb in bed generates smoke (7)
I believe the answer is:
cheroot
'smoke' is the definition.
(I've seen this before)
'heart-throb in bed' is the wordplay.
'heart-throb' becomes 'hero'.
'in' means one lot of letters goes inside another.
'bed' becomes 'cot' (cot is a kind of bed).
'hero' placed inside 'cot' is 'CHEROOT'.
'generates' is the link.
(Other definitions for cheroot that I've seen before include "smoke" , "One smoked" , "Square-cut cigar" , "Variety of cigar" , "Havana?" .)