Non-verbal communication to show you're triggered

Have any of you agreed with your T on some 'non-verbal sign' you can give them when you're triggered (I'm thinking of during flashbacks or when you start dissociating, but could be for other things as well of course)?
If so, would you mind sharing what you've come up with?

We're currently trying to find one for me, I often have difficulties to talk when I start having flashbacks. But I'd want to let my T at least know that there's something going on. Currently he's only really able to reliably catch it once I'm already way too upset. I think he would possibly be able to recognize my eyes starting to look different but since I have them closed almost constantly, that doesn't really work either. So we're trying to come up with something I can do to let him know.
Any ideas are welcome.

Yes, could you hold something in your hand and when you feel triggered, drop it? This has worked for me with previous Ts.

I know this isn't probably helpful because you keep your eyes closed anyways, but for me, when I freeze, I close my eyes and look away. Sometimes, I'm able to catch myself before I freeze and I simply tell her "stop". We then stop and talk about my dog to get me to come back.

Could you just hold up your hand, like "stop"? Or perhaps the timeout sign (making a T with your hands--my H does this sometimes to pause conversation because he works as a referee for a youth sport).

T can typically see in my eyes when she is losing me. If not I usually put my head in my hands. So she will ask me if I am still with her. If I am, I will either say so or shake my head. if I am it with her, I don't respond. djr had started to recognize when she is losing me so asking me if I am either her usually brings me back quickly

Thanks, now I have a few ideas! Had kind of trouble with coming up with anything before.

Former T could tell because I would sort of stare off in space or stare at a wall. I don't think regular T knows and I don't get triggered as much with her or dissociate as much with her. We don't cover as intense of stuff either though. Maybe make a little stop sign out of cardboard and hold it up when it is getting too intense?

For me, there is something new and reinforcing about actually using words to say no. Don't overlook the strength of a short and direct "No".

I think we kind of just stumbled upon noticing what I do to try to calm down as my stress levels increase (trace things or some other tactile action) and let ourselves pause in those moments. If the silence goes on too long, T will then do something to break it - sometimes it's a check in, sometimes it's a redirection. I think a lot of that is based on how i have been responding during the silence.

Sometimes the things we do are pretty subtle. I would guess that you probably have some tells or behaviors you do as stress increases. Granted there's always the 0-60 instances that happen so this isn't foolproof. As we were able to slow down that to more like 0-20... then 60 if not caught, we were able to find places and ways to communicate. Sometimes I would say that I don't want to be here anymore (it took a while for her to really grasp that I meant with this topic, mental space and not at session or with her). A few times I asked her to change the topic, and again that took a while for her to realize that I need her to redirect us to a random nothingness topic - like football comment or math thing --- something that engaged me differently.

Squinting of the eyes

I just get really quiet and will refuse eye contact. And then she will ask me what else is going on or what else I want to talk about and I’ll say “I don’t know” that’s usually when I’ve shut down. She does notice and she’ll say “I feel like when you say that there’s something your holding back.” Most of the time then I can say what I am feeling or thinking.

You can both start being aware of your particular patterns of zoning out or heightened arousal as they happen. The "symptoms" of hyperarousal of the nervous system are fairly similar across human experience, s it shouldn't be too hard for your T (I'm kinda blown away that he doesn't already know how to recognize a trauma response when he sees it). But it is true that everyone does have their own unique set of ingrained responses.
Anyways, if you and he reflect on past experiences of you becoming hyper (or hypo) aroused in session it shouldn't be too hard to identify your particular responses. My own are quickened breath, still body, averted and fixed gaze. Once you know what your particular responses are the onus should be on YOUR T, not you, to notice the physiological response and respond to it.
Also communicate with your T about what responses are helpful for you and which are not.