This just explains the context of the Babalon Working. It's just another example of summoning a demon, and letting it possess your body and communicate with you and others. In this case, you fuck a girl WHILE POSSESSED and impregnate her. They believe that this somehow puts demon energy into the child that is conceived.
Personally, I think nurture can override anything that this sex magick does.
Waste of time for most people to read this book. You would do better to pray to God.