Model is erotic type (9)
I believe the answer is:
blueprint
'model' is the definition.
'erotic type' is the wordplay.
'erotic' becomes 'blue' (blue can mean pornographic).
'type' becomes 'print' (both can mean printed text).
'blue'+'print'='BLUEPRINT'
'is' is the link.
(Other definitions for blueprint that I've seen before include "Original design" , "Technical drawing" , "Original plan influencing subsequent decisions" , "Design or guide for making something" , "Design plan" .)