easiest way to use one bt device with mac and iPhone?

What's the easiest way to use one bluetooth device with both Mac and iPhone? (Not a the same time.) I have it working with a voip phone on my mac (x-lite), or with the Bria voip app and the ATT line on my iphone. What I want is step by step how to accomplish the transition with the fewest clicks. I understand that I can't use it with both the Mac and the iPhone at the same time, and that's acceptable.

But it's tedious, and I would like to switch it back and forth several times a day.