Thanks suzeeq!! I found a youtube video and discovered that I was NOT doing it correctly. I was slipping the stitch Knit-wise AND doing the K2tog with the yarn in back. So I'm going to have to try again later to see if I can get it right!!
I guess I'd always thought that the Brioche stitch included "knit 1 stitch in the row below" or something like that...........guess not.