What to do when fasting doesn't lessen the desire for masturbation and pornography?

Our prophet says that if younger people can not afford marriage, they should fast for sexual desire or lust. question is.. 1. What to do if these desires come during fasting or at night even if I am not alone in my house? 2. How many days should I fast? (Even if I fast on Monday and Thursday, my desire comes another day) 3. It is said you have to busy yourself, but what should someone do during the night if desires manifest themselves during sleep? 4. What to do even when so much zikr, praying salah, reading religious books or seeking refuge from shaiytan doesn't seem to lessen the desire to view pornography, or masturbate?