I know what you mean, I have read that part too, I (emphasis here), do not think that, that accounts for sexual immorality. Imagining a woman IMHO is just innate and completely harmless, its just the way that it should be because what is the otherwise here? If you too, agree to the definition of sexual immorality as the evil ascribed to sexual acts that violate social conventions[SUP]1[/SUP], then the biological happenings are an exempt as the definition confines us to the social context. Thus, I find not, masturbation and/or being in possession of pornographic content immoral.
[SUP]1 [/SUP]www.thefreedictionary.com/sexual+immorality