You should be able to ask her to let you keep her after the first encounter, after that you can interact with her in your room at the inn.
the last one I don't know go to mystic forest I believe the name was the first area u adventure on and chose the event bag mimic and than give the D and than repeat talk to the bag mimic (u need like 5000 gold) and ask can I bring u home and pick whatever u want to say and pay up and then done u now can "use" Her in ur bedroom in the in