Couple standing in picture concerned with male sexuality (7)
I believe the answer is:
priapic
'concerned with male sexuality' is the definition.
The answer and definition are not the same part of speech. However, past participle verbs and adjectives occasionally define each other.
'couple standing in picture' is the wordplay.
'couple' becomes 'pair' ('pair' can be a synonym of 'couple'**).
'standing' is a reversal indicator.
'in' is an insertion indicator.
'picture' becomes 'pic'.
'pair' written backwards gives 'riap'.
'riap' inserted into 'pic' is 'PRIAPIC'.
(Another definition for priapic that I've seen is " Relating to male virility".)