You can do the same thing if you're on the edge, Forward-B off the ledge, and immediately turn; there was something similar in Brawl, and it was especially noticeable on Yoshi's Island (Brawl). You can turn infinitely as long as you have space to move. I assume you were considered on the stage for that moment while you were moving upward, then back in the air as you started turning.
Unfortunately, you have no hitbox while you're doing that in mid-air (actually, you might, but I think it would only hit people on the ground, like doing skid turn on the ground [I can confirm by having a Peach float right next to the ground; she won't get hit]), so it's unlikely that it's useful for anything.