As far as I know this doesn’t exist. I am also not quite sure where you are getting it from, maybe lucifer’s dogma. But E.A. has said that it doesn’t quite exist due to it not being yours etc etc. But has Lucifer ever come forth to you and said anything about it?
As for a pact, it is not selling your soul it is exactly what it is a pact. It is more like a deal, the way I see it it is just you wanting something from him and him wanting something in return for what he gives you. Like for example I want to be better versed in healing and necromancy, say Lucifer could provide that for me, say he wants me to make a shrine and do rituals to him in return. But I am not well versed on these types of things so I may not have the right way of describing it.
Have a good one.