Welcome to the forum, Evan

I think you may be talking about WILD, not WBTB. Here is the list of acronyms for reference. And if you can't sleep on your back, then don't. Everyone's different so everyone needs to tweak the specific techniques to fit you the best. I'm not a WILD expert so I can't give any useful advice about it, but search around the forum and you'll find plenty of info.

Good luck and have fun!