Proust only occasionally finding time for sexual activity (3)
I believe the answer is:
rut
'time for sexual activity' is the definition.
(period of sexual activity in deer)
'proust only occasionally' is the wordplay.
'only occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
The alternate letters of 'proust' are 'RUT'.
'finding' is the link.
(Other definitions for rut that I've seen before include "Monotonous routine that's hard to escape" , "Channel" , "It's hard to get out of" , "mate" , "Settled routine" .)