I saw Karlin's link with information on adding a second dog to the household. Since technically Elton is not part of their household, I wanted to know things I can do to help when he is around the new puppy.

I spend a lot of time at my parents house. Sometimes they have kept Elton in the past if I had to go on a business trip. I have friends here that will keep him if that ever comes up but I can't avoid Elton being around the new puppy or my parents house with me. Even if I had the time, resources, finances to add a new puppy to MY household, I wouldn't given Elton's behavioral issues. He did have another older dog in his former home, but he has too many guarding issues and we have been working on socialization which has greatly improved and doesn't seem to be a problem, but giving his history of behavior it would not suit his personality.

What should I do when I am with Elton and the puppy is there to help get them used to each other or prevent any issues? Elton is a barker and I read on the sticky that puppies can pick up habits of the other dog. If Elton is only around for a short time, will this still happen? I know that I would not leave them together unsupervised but should I keep him on a leash? Should I hold him to introduce them? They can be easily kept seperate but I don't want to put any extra pressure on my parents when going through training their new puppy.