Say something wrong seeing girl on top (8)
I believe the answer is:
misspeak
'say something wrong' is the definition.
'girl on top' is the wordplay.
'girl' becomes 'miss' ('miss' can be a synonym of 'girl'**).
'on' means one lot of letters go next to another.
'top' becomes 'peak' (I've seen this before).
'miss'+'peak'='MISSPEAK'
'seeing' is the link.
(Other definitions for misspeak that I've seen before include "say, wrongly" , "say, the wrong way" , "Express oneself badly" , "Emulate Mrs Clinton" .)