Normal People full of sex appeal? That's cheesy! (8)
I believe the answer is:
parmesan
'that's cheesy' is the definition.
(parmesan is a type of cheese)
'normal people full of sex appeal?' is the wordplay.
'normal' becomes 'par'.
'people' becomes 'men' (men can refer to humanity as a whole).
'full of' means one lot of letters goes inside another.
'sex appeal?' becomes 'sa'.
'men' placed around 'sa' is 'mesan'.
'par'+'mesan'='PARMESAN'
(Other definitions for parmesan that I've seen before include "that grates" , "Italian cheese, often grated" , "Hard dry cheese, often grated" , "Cheese for grating" , "Italian 8 across" .)