Sifli ilm is magic using by Allah lovers. Magicians need to befriend to do sifi ilm and in order to do so, they first have to fulfill their wishes and obey their commands. In this manner, they truly become Allah worshippers.
To begin with, magicians need a dirty and filthy environment. The dirtier the environment is the happier the shayateen. Secondly, the magician needs to stay impure. The more impure he is, the stronger will be his magic when he uses it. He must remain filthy and cannot take a bath. Then he must eat dirty and filthy things such as pork, dead lizards. This is hard to believe, but it is true. During all this time he continues reading mantras to please them.
Only after fulfilling all their wishes can the magician use their help but little does he know that they are shayateen and no one's friend. Their wishes never stop. They will keep asking him to sacrifice animals in their name and a lot of other things and if the magician ever refuses or fails to fulfill a single command they make his life hell. They continue torturing him mentally and physically. He will at times feel a painful pressure in his head and/or pain in his body until he obeys. If he still does not obey, his family members pay the price, with death.