How to do the ICG (Instant cube grab)?

It's a very precise trick:

1. Tux needs to touch a cube with his feet prefectly aligned with the cube's eyes. if you're too low, you'll die. If you're too high, you'll step on it. It's very precise.
2. If you don't press Action while doing that, it will be an ICK (instant cube kick). You need to press Action before landing on the cube and not let it go to actually grab it: that's the ICG
3. ICGs are mostly used in ILs because of how inconsistent they are. However, (in 0.5.1 at least) there are setups in some levels which make it easy to ICG. The easiest one is "The Escape" from 0.5.1, you just need to keep running and fall on the cube. Here's the video: