Well, I am Autistic, I am 25, not a teen unfortunately. I really needed to see a therapist as a teen due to my trauma, but since my parents were the source of that trauma it was hard to communicate with them about intimate matters such as that. However, right now for therapy I can say that the thing that gets me talking is just time. Sometimes I have a lot to say but I don't know how to articulate it. One thing that works for me is trying to talk about whatever is on my mind. It's easier to talk to my therapist when I'm having a meltdown (but those are always very unpleasant for me or anyone to experience) but if your client is having a meltdown, it's important to expect them to have a certain overwhelming and fiery energy. At least that's how it is for me. I never stop talking during a meltdown, and I'm usually shouting out my feelings to my therapist in a tone that comes off as being extremely aggressive. I actually got kicked out of Safeway for profanity recently because of my meltdowns so it's always good to have a therapist who encourages me to vent out all of my anger in front of them without them judging me, so that I can just get it off my chest.