Just take it slow, treat it (and yourself) with respect and you'll be fine - meaning start off with small, measured doses and work your way up from there.  Truth is, even with extensive prior psychedelics experience, there's only so much that can possibly prepare you for where you and your friend are headed.   

Practice focusing your intentions now, and as you work your way through the extraction process.  The key is SURRENDER.  Get that down, and you and your buddy are golden, guaranteed.