My answer to How can I summon Zepar?
Answer by Alex Sumner:
First of all, Goetic demons, like Zepar, are not human friendly. They are in fact very dangerous. It is because they are dangerous that they are powerful.
This does not mean that one should be terrified of them. The elaborate procedures laid down in thefor evoking Demons are safety precautions for dealing with spirits properly.
Perhaps the reason for your apparent failure to summon is Zepar is unrealistic expectations of what happens when Goetic spirits manifest? If so, I recommend reading the accounts of what other magicians have experienced when working with the Goetia, e.g. Lon Milo Duquette’s.