Two Apple devices using one ID one with restrictions and one without

I have two Apple devices that I want to use the same Apple ID on. One of the devices I would like to restrict with parental controls and the other one I don't. How can I set it up so that one has the restrictions and the other one doesn't under the same Apple ID? I set up one device with the restrictions and it placed the same restrictions on the other device. How can I avoid this?