Smoke with champion in bed (7)
I believe the answer is:
cheroot
'smoke' is the definition.
(type of cigar)
'champion in bed' is the wordplay.
'champion' becomes 'hero' (synonyms).
'in' indicates putting letters inside.
'bed' becomes 'cot' (cot is a kind of bed).
'hero' inserted inside 'cot' is 'CHEROOT'.
'with' is the link.
(Other definitions for cheroot that I've seen before include "16 21 [INDIAN IMPORT]" , "Cigar with ends squarely removed" , "'Cigar, square at both ends (7)'" , "Small cigar" , "smoke" .)