That man tells stories, including primarily clever twists (7)
I believe the answer is:
helices
'twists' is the definition.
(I know this)
'that man tells stories including primarily clever' is the wordplay.
'that man' becomes 'he' (he refers to a man).
'tells stories' becomes 'lies' (tell stories can mean to lie).
'including' is an insertion indicator.
'primarily' says to take the initial letters.
The first letter of 'clever' is 'c'.
'lies' enclosing 'c' is 'lices'.
'he'+'lices'='HELICES'
(Other definitions for helices that I've seen before include "spirals downwards, perhaps" , "curves" , "twisting forms" .)