I cant speak to why your treatment provider wanted you to bring something in to therapy with you but I can tell you why my treatment provider told me to..

he wanst trying to manipulate or trigger me to switch.

therapy is about going to a treatment provider to work on hard to handle problems. sometimes doing that will cause anyone whether they have a mental disorder or not to feel triggered.

feeling triggered means feeling emotional.

my DID / depersonalization derealization, amnesia and so on were/are dissociative meaning any time I encountered something that made me feel emotional I would dissociate. I would feel numb, spaced out and when I wasnt integrated would switch into and out of alters during therapy.

my therapist wanted me to bring something in to hold so that when I was feeling emotional, instead of dissociating I could use that personal object to stay grounded, to not dissociate....

example storms were one of my triggers. my therapist was not a mind reader, they could not jump into my brain and know every single thing that caused me to feel emotional.

if I was triggered (feeling scared, sad) when my treatment provider asked me about the weather that day (talking about the weather is just a normal thing, people wake up in the morning they look outside see what the weather is and dress accordingly, turn on the news and what do you get a weather forecast...my point weather is just something every human being encounters many times a day, it normally would not trigger someone so my treatment provider has no idea that it would trigger me just by saying hi, come on in what do you think of the weather we are having today, normal conversation.

me the moment I see rain my anxiety builds, my dissociation symptoms increase. let alone answering my treatment providers perfectly innocent welcome how is your day and what do you think of the weather would send me to being spaced out and disconnected.

by having a personal object or my service dog with me I can practice self care instead of dissociating. I can look at the object, notice its colors, texture, how cold or hot it feels, breath and calm myself then look at my therapist and say to him I dont like this weather, it scares me, it reminds me of when I was abused in a mine shaft and had to find my way home during a thunder/ lightening rain storm.

in other words therapy is about hard to talk about things and my bringing my service dog or a personal object helps me to continue to participate in therapy while at the same time ..........not.......have my anxiety, depression, dissociative disorders interfere with what we need to do.

my suggestion would be to talk with your treatment provider, they will explain to you what your treatment goals like whether or not therapy for you will naturally be talking about hard problems that you are seeing them for, and why they asked you to bring a personal object in with you.