Has sex with fashionable sort of girl in a small room (6)
I believe the answer is:
bedsit
'a small room' is the definition.
(a bedsit is a small room or residence)
'has sex' is the wordplay.
'has' becomes 'beds' ('bed' can be a synonym of 'have').
'sex' becomes 'it' (a common euphemism).
'beds'+'it'='BEDSIT'
'with fashionable sort of girl in' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for bedsit that I've seen before include "Small flat" , "Room to accommodate" , "Single room for living" , "One-room home" , "One-room flat" .)