It's very unlikely that I'm going to land one on friday, but if I adapt my roundoff well enough, it could happen.
The only way I can think about going for this is into a pit, on a trampoline, and back tucks onto mats. Obviously you can't roll out of a back tuck and a half, so I'm just trying to find ways I can practice this safely. I'm not going to just throw them randomly, don't worry. I tried a double back on a sucky trampoline once and freaked, thus landing on my neck. I never want that to happen again. It's been months and I can still feel it a little.
The funny thing is though, I don't find them scary. Learning single back tucks was scary, but double backflips aren't scary at all. They're just backflips held longer to me.