Not sure if this is already known or not, but I'll throw it out there anyways. When you use the up B in the air, when it finishes you fall and topple over or whatever. When you do it on the ground, there's some sort of animation after he's done spinning. Either way, there's some lag after the move.
If you finish the spinning kong as you're just above the ground, then instead of toppling over, DK just goes into his normal standing position. That is, there is no lag after the up B and you can proceed instantly into a jab combo or grab or whatever you want. The timing is slightly tricky at first, but it is really not difficult to do once you get used to it.
I find it easiest to do on stages with platforms because you can simply up B cancel your jump so that you end just above the platform. For example, on battlefield you can jump and up B really quick to hit your opponent and drag them onto a platform (kind of like MK's cyclone) and then instantly grab them and throw them off the stage for bad times. For an even easier application, you can uair and then up B in the same short hop; if you do the uair quickly enough you can do an up B before you hit the ground and the height is perfect to cancel it on the platform above. At low enough percents, after the uair they will be caught up in the spinning kong and then, again, are fair game for a grab on the platform.
Anyways, aside from stages with platforms, green greens, and lylat cruise, it is not really helpful since you're vulnerable trying it off the ledge, but it's still nice to throw in every once in awhile. After all, a well-placed spinning kong can do like 35%.
