1. Write a "coming out" letter to read to them at the therapist's office;
2. Tell them that there's something really important that they need to come with me to in a couple of weeks;
3a. Endure my mom bugging me to know what it's all about for two weeks;
3b. Make extra sure all of my incriminating evidence is well hid, as she'll become extra snoopy during that time frame;
4. Get them up to the therapist's office and actually do it.
Step 1, and possibly 2, are going to be easy. The others? Not so much. I will, of course, let you guys know how it goes. If, after that time, you don't hear from me again, well, that means something bad happened.
EDIT: Asta, just because I've always wondered - double-blind means that the subject doesn't know both what the test is really about, or that they've been given the placebo, right?