Summoning a supernatural beings may be dangerous, but it depends what being a man calls.
I tried summon a lower pagan gods, and I did not need any rings.
Meditation about the name is sufficient, optionally using the mirror, using the sleep etc. It take some time, but mostly it is without any risk. See greece and egyptian magical papyry for example. There was used no cirkles.
But summoning most of demons is dangerous even when is ther any circle.