How do I export my private key on MultiBit I am using Multbit on my desktop, and I want to use my wallet on a another device like my phone.
MultiBit does not have the same dump private key options as the normal bitcoin qt. Your best bet if you want to move coins is to load your wallet of choice onto the new device, then send to that address from your MultiBit wallet. Multibit stores private keys as described here 
https://multibit.org/en/help/v0.5/help_walletBackups.html
https://multibit.org/en/help/v0.5/help_fileDescriptions.html