How do I balance on the floor?

EDGE has an achievement called balance where you're told to "Balance on the floor". I've tried to do this by partly moving to another square so my cube is sitting on it's edge but it seems to immediately fall over or back to the original square and no EDGE time timer appears. What am I missing?

The trick is to tap the key only very slightly until the cube starts moving, then, right before the cube passes the edge, release the key and let the cube fall down, and then, in the very last moment where it is stil falling, press the key again to prevent the cube from touching the ground. It of course completely depends on how precise you are (I did it with a mechanical keyboard with made it a lot easier compared to trying it with a laptop keyboard first), but after 5-10 minutes of practicing you should be abto to do it quite easily. Also, no EDGE timer will appear, so it might help to get a feel for how long 5 seconds are first, because the achievement is not awarded when you beat 5 secends, but when you touch the ground again.