argh... I tried that a few times but it didn't work for me

I was afraid you might blow your brains out. Did you crouch in the funnel?
I think I found it accidentally somehow. Or I think I was testing to make sure it wasn't possible and then bingo I was standing on top of the grating, so I decided to make it the solution.

Yes, I crouched but it needs the correct timing and angle. Now i feel like a franken-wisperer. I spent so much time with my little friend. Because of its asymmetric shape its possible to throw it backwards almost twice as far as a normal cube. He does at least 6 backflips with awesome style scores. 10/10

Haha. You threw him across the grating? Geez, there's no way that should work!
I don't know about timing and angle for the final trick. For me it seemed to work "every time":

https://www.youtube.com/watch?v=jwud6EuxXew#t=48