Find and read the Letter to Bodies of Elders re: Pornography.
Figure out exactly what kind, how often and whether or not you masturbated to it. Be careful! If you pick stuff that the WT deems too "debased" you may end up Disfellowshipped. Anyway, if you admit to just the right blend of porn and wanking, they will have no choice but to remove you immediately.
Just a thought.
om