Keeping a horrifying secret is like making sure the most dangerous prisoner is on lock down, and does not escape.
You are hyper aware of this secret, it makes you hot and you sweat and squirm, but yet you're cold as well.
You have been holding this secret for so long that you no longer worry about letting it slip, but then you do, and the other person always catches on.
And they don't know how to react, but they try to be your friend and help you, but it only makes it worse and you can't be angry with them because they are trying.
Words are so much more difficult to use now, because the secret is choking you, and now it's choking someone else too and it's all your fault.
Stop speaking, no more words, do not respond, just become a shell of your former self.
Go back to being normal when the secret fades from their memory, and put the prisoner back where it belongs.
Deep in the cell of the brutal prison that is your mind. Keep watch on that prisoner and do not let it out.
I think we all may have some secrets that are very deep and personal that we want to share, but probably won't ever share.