Awkward relations holding writer up (5)
I believe the answer is:
inept
'awkward' is the definition.
(I know that awkward can be written as inept)
'relations holding writer up' is the wordplay.
'relations' becomes 'it' (both can mean sex).
'holding' is an insertion indicator.
'writer' becomes 'pen' (something which writes).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'pen' back-to-front is 'nep'.
'it' going around 'nep' is 'INEPT'.
(Other definitions for inept that I've seen before include "Awkward, showing no skill" , "Unskilful, awkward" , "Clumsy - silly" , "Silly or senseless" , "Lacking skill" .)