Suppress issue about sex (3,2)
I believe the answer is:
sit on
'suppress' is the definition.
(I've seen this before)
'issue about sex' is the wordplay.
'issue' becomes 'son' (issue can mean someone's offspring).
'about' indicates putting letters inside.
'sex' becomes 'it' (a common euphemism).
'son' enclosing 'it' is 'SIT ON'.
(Other definitions for sit on that I've seen before include "Delay dealing with" , "Suppress" , "Fail to deal with" , "Use as chair; fail to progress (file)" .)