If I'm struggling with a defilement, I tend to find that simply including it in Mahasi-style noting doesn't cut it.  It wants / needs more attention.    Sometimes I have to back off from noting in order to give it lots and lots of room to fully express itself, then can return to noting.  Thoughts?

howdy.
cutting it off at the root can work although its like quitting smoking cold turkey.

repeating behaviour (bad or good) increases the strength that behaviour has to take over.  nicotine is a poison but in small amounts creates exciting neurotoxins.  when we stop using it our brains habitual tendency doesn't care if its poisonous or not it is simply accustomed to this excitement and makes us uncomfortable until it gets to squirt out more of thos neurotransmitters.  the more we feed that cycle the deeper the habituational groove.

behavioural change isn't easy.  whether smoking, porn, hating your ex, coffee every morning...but stopping it is stopping it and after a while it will get easier.

off base?

I am also wondering what you are noting when you decide to give up; in other words,how far you are breaking down the sensations that compose the arising defilement. So if it's a desire to gossip, for example, you can note restlessness, but you might also note a constriction in your throat, an agitation in the region of the eyes, and a twitchiness in your hands, and as you keep going you'll note a feeling of emptiness in your abdomen, which then translates to a metallic taste in the mouth, and a tension in the heart center--you get the idea. As you go more deeply into it, the sensations become more and more subtle, and take you away from the thought-stream that may have started it. 

And now I should just go take my own advice!