Take in circuit ahead (3,2)
I believe the answer is:
lap up
'take in' is the definition.
(lap up can mean to consume enthusiastically)
'circuit ahead' is the wordplay.
'circuit' becomes 'lap' (synonyms).
'ahead' becomes 'up' (similar in meaning).
'lap'+'up'='LAP UP'
(Other definitions for lap up that I've seen before include "Delight" , "Drink (water) like a dog" , "Take in avidly" , "Scoop" , "Relish (with the tongue?)" .)