I've had to retrain a pug and a chihuahua not to bite me when clipping their nails. The pugs' nails were left to grow and ended up growing into the pads of the foot. The vet wanted to put the dog to sleep to trim the nails. She now lets me trim the nails-with a dremel-without trying to bite.
The Chihuahua was put under to trim it's nails before I had it. It took me six weeks to just touch it's feet, but after that we were able to move very quickly and cut it's nails within a few weeks. It does take a lot of time-but it's worth it.
