Okay this is kind of a hard one to follow and even harder to actually do so bare with me. When the Ice Climbers use their Down B while running they get a little bit of sliding distance. Run toward the edge of any platform or stage and use their Down B just as they're about to leave the ledge. What should happen is they fall off the side of the ledge but do their Down B as if they were on the ledge (both facing opposite directions.) Now here's where it gets hard. Go to the top platform of battlefield to test this. If you do this at a very specific distance from the ledge of the platform, what will happen is Nana will slide off the ledge, doing her down B toward the center of the stage while Popo remains on the top platform doing his down B toward the edge of the stage. After the down B is finished, Nana floats just below the platform for a second before magically teleporting back to you. During the time that she is floating you can input any command with popo still standing to make her do the corresponding aerial. From there you can alternate commands. This is ridiculously hard to do and anyone who could do it consistently would be my hero. Not sure how useful it could be either but it looks really sweet when you hit someone with Nana with it. Sorry I can't make a video you'll have to test it out and if anyone finds it useful or can do it consistently can make a video.