Actually one of the very hardest.
First, define the problem. Sexual issues are problematic. While STD's are bad because they cause harm, sexual issues are often 'bad' ONLY because some society says it is (
homosexuality,
masturbation, pre-marital sex, ..a very long list). If someone had BDSM that was pleasurable and fulfilling but also had intrusive guilty thoughts about it, would the issue be the BDSM or the thoughts. If someone had sexual activity that was messing up their other life issues is it addiction or time management issues?
Then, generally on addiction. Several points. Addiction is defined by inability to stop an activity that is actively causing harm. Liking hair pulling but not any actual damage by itself is not going to fit this, for example. The fundamental problem is that the part of the brain determining immediate action, emotion, pleasure, orientation gets all the sensory input and acts immediately prior to conscious thought. Programmed societal reactions are in the middle somewhere. You cannot change this. And, you can overwrite many of the immediate reactions.
Find triggers, avoid them. If cinnamon rolls on the counter make you eat them, don't buy them.
Substitution of other activities from addictive ones or less harmful ones. If this works.
Transcend. If you need to study AND you want to be submissive. Have a study buddy who really really demands that you study.