The most common and most likely answer to this crossword clue is the 4 plus 2 plus 6 letter word TALK AT LENGTH
I've seen this crossword clue in The Daily Telegraph
T
A
L
K
A
T
L
E
N
G
T
H
Buddy explains!
The straight part
We know that "What one is encouraged to do on a psychiatrist’s couch" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what one is encouraged to do on a psychiatrist’s couch = talk at length.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.