I got them alone and was all like, "SO. Do you know what transgender is?" And then they'd be like, "Yeh, why, are you?" ".......Maybe."
Or I'd do a huge preamble about like, Are you sitting down, I have something to tell you, it's kind of a big thing, and just make it seem like I was about to tell them some big awful interesting thing, and go with that until they got upset and was like, FOR FODD'S SAKE, just TELL me already! And I'd be like, "Okay. I'm transgender." And they'd be so relieved to finally know, that they wouldn't bother getting upset about the reveal, cause they'd be anticipating the WORST case scenario things.
Rambly preamble seems to be my default defense mechanism.