You have you reboot the iPod. Meaning that all the songs, movies, data on the iPod will be lost. Then is will be unsynced. Or just don't let your friend connect their iPod to your computer.
You can sync it by plugging it in. There isn't a 'unsync' button. If you turn off the iCloud functions, it will slowly drift 'out of sync' as you use it. You can delete all the user data, which will REALLY put it out of sync.
Yes. Connect the ipod to another computer with itunes. Then when itunes pops up click "Yes" in the dialogue box that pops up. The box asks you if you want to erase the sync and make a new sync. If you don't have a computer, on the ipod go to Settings > Reset settings.
You can get rid of Facebook moods, if you unsync your setting.
Go to the pivacy, There should be an option to "Restore factory settings". It will erase all accounts off the phone, and all apps and memory you have downloaded. The other way would be to go to "settings", then "Accounts and sync", then click the account you want to unsync, and click the 'Unsync" button. But the problem I ran into with that method was that the device needed the account to run alot of apps and told me I couldn' unsync, so the factory settings is the only way to really do it.
no matter what any1 says i havent been able to get this done
The iPod nano was not the first iPod; the iPod classic (at that time the iPod) was the first.
it is correctly spelled iPod.
This ipod manage software can transfer the files from ipod to computer, ipod to iTunes, and iPod to iPod: http://www.ipodtransfer.net/how-to-transfer-ipod-file-with-ipod-transfer-software.html
ipod nano
You have to find how you synced that person's computer to your and break the connection and then restrict that computer to get the connection. This is to be done using the some software. You can turn of sharing setting and restrict everything.
This ipod manage software can transfer the files from ipod to computer, ipod to iTunes, and iPod to iPod: