Next time you're stuck with him and he opens his big mouth, just say "Hai Sensei! With your great knowledge I'm sure you'll be receiving your 5th dan soon!" and laugh
Then if he doesn't loosen up, explain to your instructor that you cannot work with this individual any longer as you are unable to concentrate with his constant chattering in your ear.
If your instructor doesn't move you to work with another partner and DEAL with the situation, then you may have a bigger problem...