I have had friends with DID (I do not). I did not know at first they had DID. It was not until they started trusting me, they let me know the little "quirks" I had thought were "mood swings" or "forgetfullness" or simply "imagination" was actually different "alts" coming out.

So really .. since I was able to explain it away in my mind, they never had to - until they wanted to. My advice to you would be to simply tell them "there are times when I am stressed I start talking about/typing about what I am thinking without realizing it - but I don't want to talk about those things now, maybe later, I hope you understand." If they keep pressuring you tell them you need them to respect your wishes or you will not be able to keep speaking to them.

That's until you are ready to be open about it anyway.

Just my two cents for whatever its worth.

Good luck!