Until today all I needed as a minimum to make me have to wank was to see a pair of boobs hanging, a naked women with public hair, a large heavy pair of boobs moving whilst braless either out or under loose clothes, a pic of any women I know exposed.
But found out today a friend used to rub her pussy over seeing my cock, she went into quite a lot of detail about what she liked and what got her worked up and told us of occasions she has fingered herself whilst watching my semi erect cock swinging about.
So it now turns out I will masturbate over just the thought of a women looking at me a playing with herself.