Don't stop thinking of teacher receiving fine (5,2)
I believe the answer is:
dwell on
'don't stop thinking of' is the definition.
I can't judge whether this defines the answer.
'teacher receiving fine' is the wordplay.
'teacher' becomes 'don' (don can mean an academic - especially at Oxbridge).
'receiving' is an insertion indicator.
'fine' becomes 'well' (similar in meaning).
'don' placed around 'well' is 'DWELL ON'.
Can you help me to learn more?
(Other definitions for dwell on that I've seen before include "Think at length about" , "Mull over" , "Speak at length about" , "Ponder about" , "Linger over" .)