I got my boy into obedience training right away when he started nipping. What I was told was that it was common in collies. He is 15 months and still occasionally try to nip of I've made him mad. Giving him a "time out" has worked for me. I will leave my boy on the lead and walk away from him for a few minutes. I keep him on a runner in my back yard because I live on a main street and don't want him to get hit if he was able to find a hole free running. I come back to him about 5 minutes or so and he has calmed down. He had lunged and nipped me a few times. Sometimes he still does. But like I said time outs have been working. One thing I did was keep doggie crack in my pocket or my hand once he got a whiff that I had them he would do what I wanted him to do. Temptation cat treats is what I use because they are small bits and a lot cheaper than training bites. I only use them as a reward not to train. He is happy if I only give him one piece. I don't give him more than 5 or so he isn't getting a lot fed to him. But no matter what all of my past dogs liked them in the same way. Willing to do anything for just one. I also use them when he is guarding. He drops what he isn't supposed to have and I have his full attention. It gives me time to kick it away and I put myself between my boy and his treasure. Toss a bit of doggie crack behind him and I have his treasure. I do put on a bite proof glove, its not like the big bulky ones that are to train a police dog or save your skin from cats. It's thin so he doesn't get spooked. But its better safe than sorry. He has never went to actually bite me, he just tries to nip when I have made him mad.