I can understand the hard getting out part of this. short version in order for any of those that lived inside of me to come out I the body born (what you call the host) had to be so uncomfortable\ upset \ triggered which ever word you use, so that I had my dissociation problems (feeling numb, spaced out, disconnected) this dissociating in me is what caused my alters to come out / take control. who came out depended upon what was triggering me to have my dissociation problems and who took care of that problem...

my point if its part of your sense of agency (job, purpose reason why you are there, and all that stuff) to talk about how you and the host are doing it will happen, its just a matter of when....

heres a good tip, you said you were able to do this before (come out and talk with the therapist) my suggestion is look back at that time and see what all the dotted I's and crossed T's were that enabled you to do that before. that will tell you when the right time for you to do it again can happen.

if it turns out that you cant talk with the therapist for some reason maybe there is someone else inside that can do that for you. each persons internal system is comprised how ever and with who ever is needed to take care of and ensure the survival of everyone. my point if its not your sense of agency to talk with the therapist and the last time just turned out to be a lucky fluke maybe who evers job is is to do that can help do this or fix things so that it can happen for you.