GSD puppy interaction with Chihuahua puppy?

by Matt C.
(Miami)

My fiancee and I have a 14 wk old GSD pup named Diesel. A very happy pup that is doing quite well with his training. However, we recently rescued a 9 month old tea cup chihuahua, Lexie.

I've been proactive about their interaction, but Diesel being about 30 pounds, is consistently biting at Lexie (about 4 pounds). She is fighting back and I am currently trying to keep him at bay from her because he doesn't know his own strength.

What is a good way to get these dogs to socially interact well and keep either of them from getting hurt? I am currently teaching Diesel German instead of English, so the NO and leave it commands are doing O.K. at the time of the incident, however, I would like to see the incidents stop totally. Thanks for your help!