I think your mindset has a lot to do with lucid dreaming, especially in your case and a lot of cases with WILD. One night, when I woke up from a lucid dream, I immediately tried to go back in but I couldn't for some reason. Looking back I realize that it could have been a lot of things, but the thing that stood out the most was the fact that I was simply trying too hard to go back in. What I really needed to do what just let myself in instead of struggling. It's kind of like trying to break down an unlocked door. With WILDs you have to have a relaxed and passive mindset with intention of what you are doing in the back of your mind.
Of course, it simply could have been that you were just lucky that one time. I had my first WILD by accident. So my advice to you is to just relax and not think so much about it, and perhaps deeply analyze everything little detail of that night when you had that floating sensation and what you should replicate and what you should add onto it so you can be even luckier next time.