How do I recognize a direction of rotation?

Hello,

I got a little confused somehow.

If I place a coin on a table with its face parallel and then rotate the coin around the perpendicular, how do I know whether the direction of rotation is right or left?

I just read that you look at the top half of the surface, but that can't be the explanation. How confusing would it be to teach that to children when the bottom part of the coin actually rotates to the left.

And it gets even weirder when you look at a point. How can you tell whether it's rotating left or right if it doesn't have a surface where you could say that.

I look forward to your reply!

LG