I've got a 10 week old that I'm ready to leash train. He's used to a collar (cat collar w/ a bell- great idea if you too have a vanishing puppy). Any advice? The leash around his neck is scary to him right now, but I'm determined to train him to not pull. P.s. He's a lab/shepherd/terrier/boxer mutt. I call him my grab bag puppy- not sure what he'll turn into. I'll post a pic once I figure out how to.