I am unique, one of a kind. There's no one like...

I hide what you don’t want left in the open. I move only a short distance, yet always return to the same place. I hold order inside a larger frame, and I wait in silence until a hand pulls me into the light. What am I?

I go up and down, And most associated with a fly I can close a gown And my teeth can bite, especially if you're a guy

Neurons of a beast unliving, Or with razors, zinc and steel. Gold bonded: either nothing or something my host comes alive but neither thinks nor feels.

The name is misleading, how could it be not, for relaxing rarely happens, while sitting on the pot.