Every Consensual Predator is the same: meet them inside of an Apex Predator stomach. You can use 'Predator Info' button in-game to see her current location (whether outside, or if eaten will say by who)
Yes. If you click 'Help' button in-game, there's a section called 'Predator Tips - Spoilers' that has tips on every predator. Find the page for Erinna and it should explain everything. If it doesn't, I can elaborate further and consider updating the tip