Here goes my thought process:
I believe the hand's purpose goes hand in hand with the colors.
If the colors are going in the order of Red, Blue, Green, Yellow, then I can place the hand and then simply guess what the color will do for said person. On N1 it was red, so knowing it would change to blue, I thought it would be a cop thing perhaps, I mean blue is an authorative color. the next day, because people kept talking about reflections, I assumed I was right and kept saying it was I who blocked Aqua because my action would run before anyone elses, including Omni's. Then when I knew it would change to green, I placed it on myself because I wanted to hope it was green for healing, having survived I assumed I did well. I don't know what yellow does, but I placed it on Notty after feeling that suddenly agreeing with me when going for a Vyryn lynch striked me wrong because Notty was quick to put me down on anything I said, similar to Aqua earlier in the game.