How do I recover restriction code without a computer

Go to Settings>General>Reset>Erase all contents and settings. Then set it up via wifi.

If earlier iOS you will have to then connect to computer and restore via iTunes.

- Restore from a backup that was make before you added the Restrictions passcode. If you restore from a backup made with the Restrictions passcode the Restrictions passcode is also restored.

- Restore to factory settings/new iPod.

- If you are up to it see:

How to reset forgotten Restrictions...: Apple Support Communities

How to reset forgotten Restrictions...: Apple Support Communities