To snooze during sex is awkward (5)
I believe the answer is:
inapt
'awkward' is the definition.
('inapt' can be a synonym of 'awkward')
'to snooze during sex' is the wordplay.
'to snooze' becomes 'nap' ('nap' can be a synonym of 'snooze').
'during' indicates putting letters inside.
'sex' becomes 'it' (a common euphemism).
'nap' going inside 'it' is 'INAPT'.
'is' acts as a link.
(Other definitions for inapt that I've seen before include "Free from deceit" , "Far from fit" , "not seemly" , "Not fitting" , "not fit for purpose" .)