I think the water is held together because the spinning causes the water to spiral upward, holding it in place.

ITT: facepalm.

It's nice that we all know physics. Sonlen, the constant of gravity is so amazingly miniscule that the water exerts nanonewtons or so on itself.

I got it to work, but I had to use some black magic. I'll give you guys the spell, if you want.

Cheers, I'd appreciate having that so that I can wow friends and family with my amazing water-spinning skills.

So wait, is this real or not? I think it is fake `-`

I think it is real.

I highly doubt this is real, unless a few things happened that we weren't told about:
1) Agreed on the viscosity of the liquid, or maybe some colloid would be better.
2) Some sort of seal placed on the inside of the cup which contains the water, and allows it to maintain its form.
3) Assuming the spinning part mattered, which I doubt it does, then you would have to find some way to spin the cup fast enough that it would maintain enough energy to keep its state. I don't see spinning it with your hand doing that at all.

So my best assumption is a colloid of sorts with a semi-permeable outer shell. Maybe something like a cell, except keeping the water contained instead of the cell. e.g. the hydrophilic part would be pointed in.