Thanks @firewns and @Yeos for the useful advises. I think I haven’t do Asubha bhavana seriously enough, so I will try harder in this respect.
It’s been 7 months since, and I made quite a drastic progress in the Path, but to be honest the Kama is still there, but the situation is a bit weird:
In the day and the evening, I live totally aware of my body, feelings and thoughts (I’m try to practice Satipatthana 24/7), Kamavitakka (or Byapadavitakka or Vihimsavitakka) would be destroyed as soon as they arise. I keep Sabbaasava Sutta in my heart for protection purpose.
But sometimes (maybe every 7 days) at night, when I laying down, Kama power seems to have multiply by 1000 and my Sati power decrease 1000 times. Maybe Mara the Evil One works harder at night I suppose. I try to not eat the trap but my power at that time was so weak, I couldn’t remember the protection Suttas that I’ve remembered by heart. So sometimes Mara still win over me, leaves behind much remorse and shame for me.
Maybe this because I haven’t got into the Jhanas yet. My situation is exactly like what described in this sutta MN25. In this sutta the Buddha said if one frequently abide in the Jhanas, one will blind the Mara, make him unable to control at will.
On the way to Stream Entry.