Blue material ripped up at ICA (7)
I believe the answer is:
Here is my best explanation:
'blue material' is the definition.
(blue can mean pornographic)
'ripped up at ica' is the subsidiary indication.
'ripped' becomes 'tore' (I've seen this before).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'at' says to put letters next to each other.
'tore' written backwards gives 'erot'.
(Other definitions for erotica that I've seen before include "writings about sex", "Blue stuff", "Material of a sexual nature", "pornography", "Sexual writings and pictures", "Amatory literature", "works to stimulate passion?", "Arousing literature or art", "literature of a sort" and "Amorous literature".)