On the iPod touch use the childs Apple ID for everything (iCloud, iMessage, FaceTime) except iTunes and app store.
Use your Apple ID here:
Settings > iTunes & App Stores
Use their Apple ID here:
Settings > Messages > Send & Recieve
Settings > FaceTime
Settings > iCloud
You can also use their Apple ID for iTunes & App stores so all nne purchases are on their account. The old purchases already on the device (or in iTunes on the computer they sync with) will prompt for the password to your account before they can be used.
so there are those of us who are adults with grown children. They have music they have purchased on our Apple ID. with their own payment methods. I purchase apps for ipad and my macbook. I also have music that I have purchased on the same ID...
(my )Apple ID. My daughter has music she purchases for her iphone. There comes a time when they grow up where they want their own ID but they don't want to lose all the music they have already purchased if they were to start their own iphone Apple ID. It sure would be a nice feature to be able to separate accounts and transfer purchases to their respective payers. Thanks for listening.