Teacher, around end of year, needing a cocktail (7)
I believe the answer is:
sidecar
'cocktail' is the definition.
(I know that Sidecar is a type of cocktail)
'teacher around end of year needing a' is the wordplay.
'teacher' becomes 'sir' (way of addressing a male teacher).
'around' means one lot of letters goes inside another.
'end of year' becomes 'dec' (short for December, last month of the year).
'needing' is a charade indicator (letters next to each other).
'dec'+'a'='deca'
'sir' placed around 'deca' is 'SIDECAR'.
(Other definitions for sidecar that I've seen before include "that biker may take with him" , "In which a passenger may be taken" , "Appendage to motor cycle" , "Part of combination" , "Where a passenger may go" .)