Doctor sticking point right in the behind (9)
I believe the answer is:
registrar
'doctor' is the definition.
(I've seen this before)
'sticking point right in the behind' is the wordplay.
'sticking point' becomes 'gist' (I've seen this in another clue. I am not sure about the 'sticking' bit.).
'right' becomes 'r' (common abbreviation).
'in' is an insertion indicator.
'the behind' becomes 'rear' (both can mean one's bottom).
'gist'+'r'='gistr'
'gistr' going within 'rear' is 'REGISTRAR'.
Can you help me to learn more?
(Other definitions for registrar that I've seen before include "Official recording births, deaths and marriages" , "Official record-keeper" , "University administrator -- hospital doctor" , "Medic" , "position in hospital" .)