INCEPTION'S ENDING*mega spoliers*

I don't understand how the ring works as a totem. A totem, as I understood it, is supposed to do an action differently in the real world than the dream world. Spinning forever vs. toppling over, chess piece falling with a slight touch vs. pushing it over, die landing on a number vs. random, not a ring appearing and disappearing. I do think the top is borked because it was his wife's, but since she died, I guess he could have taken it over for her.

A totem is an item who's properties is only known by you. So that way when you're in someone else's dream, you can tell apart dream and reality. The ring could possibly be a totem because only Cobb knows the rings weigth, size, and shape.
The ring doesn't appear and disappear. Its simply that when Cobb is in a dream, he has it on. In reality, he takes it off.