Dealing with Lust

I am wondering about the nature of lust and its remedies. I know Buddhism posits that lust depends on the sense organs, and contact with an object. Thus, I've read it promotes decreasing this contact and guarding the senses. Yet, I find myself experience lust seemingly detached from contact, or rather, lust with a subjective emphasis. It is my imaginations that flare and cause me to experience lust, but only at certain key moments. I specify this because *most* of the time, I do not experience lustful thought processes. Only at certain moments does it almost seem like my guard is down, and my mindfulness absent, and lust resurfaces in an almost obsessive way. I have not managed to find a way to decrease the periodic surfacing of lust I describe. It seems more inherent to myself as a subject than caused by objects intrinsically. In terms of remedies: (1) I wonder whether natural masturbation without erotic material is bad. Could it potentially reduce these types of surfacing lust? Or, rather, would abstinence decrease lust more effectively. I feel in this second case the libidinal drive might simply increase, whereas in the first libido is kept even. But perhaps I am wrong. (2) Is there any Buddhist information on interior causes for such lust? Thanks for any answer.