Back in pub, saying when about to drink? (7,2)
I believe the answer is:
bottoms up
'back in pub saying when' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'to drink?' is the wordplay.
'to' becomes 'bottom' (I can't explain this - if you can you should believe this answer much more).
'drink?' becomes 'sup' (to sup is to drink).
'bottom'+'sup'='BOTTOMS UP'
'about' is the link.
Can you help me to learn more?
(Other definitions for bottoms up that I've seen before include "Your good health!" , "Down the hatch!" , "Toast" , "Cheers!" , "down it goes!" .)