Climax during drink! What did you say? (5,2)
I believe the answer is:
speak up
'what did you say?' is the definition.
(phrases used to ask someone to repeat themselves)
'climax during drink' is the wordplay.
'climax' becomes 'peak' (I've seen this in another clue).
'during' means one lot of letters goes inside another.
'drink' becomes 'sup' (to sup is to drink).
'peak' going into 'sup' is 'SPEAK UP'.
(Other definitions for speak up that I've seen before include "Make oneself heard" , "give opinions boldly" , "Say things more loudly" , "State one's opinions boldly" , "Talk louder, can't hear you" .)